I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines
had some bad-filter-capacitor issues... but this time it was the
capacitors in the power supply, not on the logic board, that
were bulging and leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements
for the
nine low-V high-I filter capacitors in the power supply, in form
factors
that would fit the cramped footprint of the originals. So, I thought
I'd relate the parts list here, in case anyone else has need of such
info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the capacitors
in the power supply, not on the logic board, that were bulging and
leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements for
the
nine low-V high-I filter capacitors in the power supply, in form factors
that would fit the cramped footprint of the originals. So, I thought
I'd relate the parts list here, in case anyone else has need of such
info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC PSU
and will be looking for some replacement caps. I like to keep a spare and
I need 650 with this new AMD 120 watt quad core PhenomII 3.2 ghz CPU and
Asus M4A78E-T mobo. With Asus overclocking friendly special settings I'm
able to run it at 4.0 ghz for each core. Makes video encoding on an
application supporting multicore encoding really fly. Not unusual to get
over 350 frames/sec out of NTSC 740x480 avi's. I can make a high quality
20 chapter DVD with all the bells and whistles in about an hour. Used to
take 24 hours on a 2ghz single core AMD



--
Live Fast, Die Young and Leave a Pretty Corpse

"Meat Plow" wrote in message
news
On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the capacitors
in the power supply, not on the logic board, that were bulging and
leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements for
the
nine low-V high-I filter capacitors in the power supply, in form factors
that would fit the cramped footprint of the originals. So, I thought
I'd relate the parts list here, in case anyone else has need of such
info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC PSU
and will be looking for some replacement caps. I like to keep a spare and
I need 650 with this new AMD 120 watt quad core PhenomII 3.2 ghz CPU and
Asus M4A78E-T mobo. With Asus overclocking friendly special settings I'm
able to run it at 4.0 ghz for each core. Makes video encoding on an
application supporting multicore encoding really fly. Not unusual to get
over 350 frames/sec out of NTSC 740x480 avi's. I can make a high quality
20 chapter DVD with all the bells and whistles in about an hour. Used to
take 24 hours on a 2ghz single core AMD




Just as a matter of interest Meat, what is your preferred brand and type of
heatsink goop when working with these very high power processors? I've
recently been working with some games machines that have two very powerful
processors on the board, and have been having some thermal issues when using
'standard' white silicon grease on them, which appears to be what the
manufacturer used originally. I have today reassembled one using some Arctic
Silver compound instead, and it seems to be doing a fine job. I have always
resisted using this stuff, because it's so messy, and so hard to remove
unless you use the complementary cleaner, but if it really is that much more
effective, then I might be prepared to live with these shortcomings. Anyone
else got any constructive comments on the subject of thermal interfacing of
coolers to high power chips ?

Arfa

On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote in message
...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing
of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on minimal.
Having to decide this week whether to spend out on 6 MJ series TO3 devices
in an old Carver amp failed due to one of the driver TO3 being pushed
through a heap of white grease , so grease on pins getting inside the TO3
socket housing , so insulating partially and eventually burning up the pin .

On 8/26/2010 8:27 PM, Arfa Daily wrote:


"Meat Plow" wrote in message
news
On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the capacitors
in the power supply, not on the logic board, that were bulging and
leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements for
the
nine low-V high-I filter capacitors in the power supply, in form factors
that would fit the cramped footprint of the originals. So, I thought
I'd relate the parts list here, in case anyone else has need of such
info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC PSU
and will be looking for some replacement caps. I like to keep a spare and
I need 650 with this new AMD 120 watt quad core PhenomII 3.2 ghz CPU and
Asus M4A78E-T mobo. With Asus overclocking friendly special settings I'm
able to run it at 4.0 ghz for each core. Makes video encoding on an
application supporting multicore encoding really fly. Not unusual to get
over 350 frames/sec out of NTSC 740x480 avi's. I can make a high quality
20 chapter DVD with all the bells and whistles in about an hour. Used to
take 24 hours on a 2ghz single core AMD




Just as a matter of interest Meat, what is your preferred brand and type
of heatsink goop when working with these very high power processors?
I've recently been working with some games machines that have two very
powerful processors on the board, and have been having some thermal
issues when using 'standard' white silicon grease on them, which appears
to be what the manufacturer used originally. I have today reassembled
one using some Arctic Silver compound instead, and it seems to be doing
a fine job. I have always resisted using this stuff, because it's so
messy, and so hard to remove unless you use the complementary cleaner,
but if it really is that much more effective, then I might be prepared
to live with these shortcomings. Anyone else got any constructive
comments on the subject of thermal interfacing of coolers to high power
chips ?

Arfa
On games PC's i've gone to water cooling, blissfully quiet (apart from
the fishtank type noise!), CPU and GPU a few degrees above room temp
even at full load. Never go back to jet engine graphics card fans.
JC

On Fri, 27 Aug 2010 01:27:14 +0100, Arfa Daily wrote:

"Meat Plow" wrote in message
news
On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the
capacitors in the power supply, not on the logic board, that were
bulging and leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements
for the
nine low-V high-I filter capacitors in the power supply, in form
factors that would fit the cramped footprint of the originals. So, I
thought I'd relate the parts list here, in case anyone else has need
of such info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC
PSU and will be looking for some replacement caps. I like to keep a
spare and I need 650 with this new AMD 120 watt quad core PhenomII 3.2
ghz CPU and Asus M4A78E-T mobo. With Asus overclocking friendly special
settings I'm able to run it at 4.0 ghz for each core. Makes video
encoding on an application supporting multicore encoding really fly.
Not unusual to get over 350 frames/sec out of NTSC 740x480 avi's. I can
make a high quality 20 chapter DVD with all the bells and whistles in
about an hour. Used to take 24 hours on a 2ghz single core AMD




Just as a matter of interest Meat, what is your preferred brand and type
of heatsink goop when working with these very high power processors?
I've recently been working with some games machines that have two very
powerful processors on the board, and have been having some thermal
issues when using 'standard' white silicon grease on them, which appears
to be what the manufacturer used originally. I have today reassembled
one using some Arctic Silver compound instead, and it seems to be doing
a fine job. I have always resisted using this stuff, because it's so
messy, and so hard to remove unless you use the complementary cleaner,
but if it really is that much more effective, then I might be prepared
to live with these shortcomings. Anyone else got any constructive
comments on the subject of thermal interfacing of coolers to high power
chips ?


You answered your own question. The AMD heatsink / quad core PhenomII 955
Black Edition package comes with Artic Silver already applied. I'm using
an Antec server case that has a hole and tube in the side cover. The end
of the tube fits directly over the CPU heat sink so it draws air directly
from the outside. In back is a pair of 120mm fans controlled by the
mainboard. If the CPU temp goes up all three fans increase according to
the temp. Or you can set them to run at full speed all the time. The 650
watt PSU also has a temp sensing 120mm fan. So the box is really quiet
most of the time. But when rendering video and the CPU usage hovers
around 50% fan speed increases slightly. Video rendering with an
application that takes advantage of multi-core processors seem to use the
most CPU percentage. I've never seen it go over 50%. Most of the time it
doesn't go over 10%.





--
Live Fast, Die Young and Leave a Pretty Corpse

On Fri, 27 Aug 2010 08:29:01 +0100, N_Cook wrote:

Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on
minimal. Having to decide this week whether to spend out on 6 MJ series
TO3 devices in an old Carver amp failed due to one of the driver TO3
being pushed through a heap of white grease , so grease on pins getting
inside the TO3 socket housing , so insulating partially and eventually
burning up the pin .

I've seen pads used in a lot of high power amps. Soundcraftsmen, BGW,
Carver, Peavey, Crown all used them at some time or another. If the
devices are torqued down properly I don't have a problem with them. You
are talking about the rubberized pads with embedded compound right?



--
Live Fast, Die Young and Leave a Pretty Corpse

On Fri, 27 Aug 2010 08:29:01 +0100, "N_Cook"
wrote:

Any opinions on silipads? From my limited trials mica sheet and absolute
minimal white grease has better thermal transfer. Emphasis again on minimal.

Do the math. Silicon impregnated rubber TO-3 pads have a thermal
resistance of about 0.4K/watt. 0.0002" Mica, with silicon grease
smeared on both sides is about 0.6K/watt. Depending on your total
power dissipation, that's hardly any difference. However, if your
heat sink is undersized, buried inside a cabinet, or located in a
place where there's no air flow, it might make a difference.

http://www.wakefield.com/LinkClick.aspx?fileticket=1ULQQwz8xmU%3d&tabid=64
See Page 6-8. The example shown is for a TO-3 packaged device.

Having to decide this week whether to spend out on 6 MJ series TO3 devices
in an old Carver amp failed due to one of the driver TO3 being pushed
through a heap of white grease , so grease on pins getting inside the TO3
socket housing , so insulating partially and eventually burning up the pin .

Keep it stock. However, if this is a push-pull type of amp, where the
thermal balance of the xsistors has an effect on the bias point,
crossover distortion, and possibly linearity, I would make sure that
whatever you do to one side, the same gets done to the other.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
wrote:

Anyone
else got any constructive comments on the subject of thermal interfacing
of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann


Thanks for the insights Jeff. All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

Arfa

"Meat Plow" wrote in message
news
On Fri, 27 Aug 2010 01:27:14 +0100, Arfa Daily wrote:

"Meat Plow" wrote in message
news
On Thu, 26 Aug 2010 13:20:18 -0700, whit3rd wrote:

I recently had a rash of reboot events on my trusty old iMac G5 (1.8
GHz).
This has already had the logic board replaced, as these machines had
some bad-filter-capacitor issues... but this time it was the
capacitors in the power supply, not on the logic board, that were
bulging and leaking electrolyte.

It took an hour or two of catalog work to find low-ESR replacements
for the
nine low-V high-I filter capacitors in the power supply, in form
factors that would fit the cramped footprint of the originals. So, I
thought I'd relate the parts list here, in case anyone else has need
of such info.

C40 and C52 10V 1000 uF
EKY-100ELL102MH20D

C45, C55 and C56 2200 uF 10V
UHM1A222MPD

C47 16V 1200 uF
UHE1C122MPD

C49 10V 3300 uF
UHN1A332MHD ** this is slightly larger diameter than the
original, but it fits **
UHZ0J332MPM **right size, but less voltage margin**

C59 35V 330 uF
ELXV350ELL331MJ20S

C64 15V 1000 uF
EEU-FC1E102B

These were all in stock at Mouser Electronics, if that matters.

Hell yes it matters. I'm going to fix a year old Coolmax 650 watt PC
PSU and will be looking for some replacement caps. I like to keep a
spare and I need 650 with this new AMD 120 watt quad core PhenomII 3.2
ghz CPU and Asus M4A78E-T mobo. With Asus overclocking friendly special
settings I'm able to run it at 4.0 ghz for each core. Makes video
encoding on an application supporting multicore encoding really fly.
Not unusual to get over 350 frames/sec out of NTSC 740x480 avi's. I can
make a high quality 20 chapter DVD with all the bells and whistles in
about an hour. Used to take 24 hours on a 2ghz single core AMD




Just as a matter of interest Meat, what is your preferred brand and type
of heatsink goop when working with these very high power processors?
I've recently been working with some games machines that have two very
powerful processors on the board, and have been having some thermal
issues when using 'standard' white silicon grease on them, which appears
to be what the manufacturer used originally. I have today reassembled
one using some Arctic Silver compound instead, and it seems to be doing
a fine job. I have always resisted using this stuff, because it's so
messy, and so hard to remove unless you use the complementary cleaner,
but if it really is that much more effective, then I might be prepared
to live with these shortcomings. Anyone else got any constructive
comments on the subject of thermal interfacing of coolers to high power
chips ?


You answered your own question. The AMD heatsink / quad core PhenomII 955
Black Edition package comes with Artic Silver already applied. I'm using
an Antec server case that has a hole and tube in the side cover. The end
of the tube fits directly over the CPU heat sink so it draws air directly
from the outside. In back is a pair of 120mm fans controlled by the
mainboard. If the CPU temp goes up all three fans increase according to
the temp. Or you can set them to run at full speed all the time. The 650
watt PSU also has a temp sensing 120mm fan. So the box is really quiet
most of the time. But when rendering video and the CPU usage hovers
around 50% fan speed increases slightly. Video rendering with an
application that takes advantage of multi-core processors seem to use the
most CPU percentage. I've never seen it go over 50%. Most of the time it
doesn't go over 10%.


Yes, seems to be 'busy' video rendering that causes all the problems on the
machines I am working on. Q & D calcs show that at max chat, the two
processors are potentially using close to 300 watts of input power between
them, and the heat that this generates in them, takes some shifting ...

Arfa

"Arfa Daily" wrote in
news:dgZdo.79946$Pa3.38201@hurricane:



"Jeff Liebermann" wrote in message
...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
wrote:

Anyone
else got any constructive comments on the subject of thermal
interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop,
causing some things to be more critical. In the process of getting
it to work, I learned a few things.

1. The less silicon grease used, the better. The idea behind
silicon grease is to fill in the gaps, scratches, and gouges in the
power transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top
center of the CPU, will cause the substrate to bend, and eventually
break. I have some ideas, but nothing that can be retrofitted to an
existing motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273
Note the comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink
face, use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann


Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video drive
(or LCD backlight) circuitry.

--
Jim Yanik
jyanik
at
localnet
dot com

On Sat, 28 Aug 2010 02:04:07 +0100, "Arfa Daily"
wrote:

Thanks for the insights Jeff.

There was quite a bit of "Learn By Destroying(tm)" involved. Measuring
flatness and thermal resistance were a major exercise, but settled all
kinds of lab arguments.

Incidentally, you might be interested in how Arctic Silver works.
http://www.arcticsilver.com/products.htm
http://www.arcticsilver.com/msds.htm
Silver has a much higher thermal conductivity (410 W/m*K) as compared
to zinc oxide (21 W/m*K) and aluminum oxide (30 W/m*K) which is what's
in common thermal compound.
http://en.wikipedia.org/wiki/List_of_thermal_conductivities
However, if your shove an ohms-guesser into a puddle of Arctic Silver,
it's not conductive. That's because the particles of silver are so
far and few, that the bulk of the solution is polyolester or mineral
oil, which insulates the particles from each other, preventing mutual
contact. However, if you tear apart a CPU/heatsink that's been used
for a while, you'll notice that the Arctic Silver is a thick and dense
paste which is conductive. What has happened is that the polyol ester
mixture has evaporated sufficiently to provide contact between
particles. Since thermal conductivity is best through the silver
particles, the result is a superior thermal connection, with the
sliver particles filling the voids. You could do the same thing with
silver dust, but it would difficult to handle and apply. Meanwhile,
ordinary silicon grease does the same thing, but there's a difference.
The oil does not evaporate as easily, and the ceramic particles are
much larger and less compressible than the silver particles. Fewer
points of contact and lower thermal conductivity of ceramic, means a
worse thermal connection.

All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core). I had an Alpha CPU machine to play with for a while, which
would burn my hand from the hot air coming out the back.

If you have a power line wattmeter or a Kill-A-Watt meter, I think a
measurement would be helpful.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video drive
(or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box /
Playstation type boxes. Apart from some support circuitry in IC form - which
admittedly does gobble enough power to make it run hot enough that a degree
of heatsinking to the pcb shielding via thermal pads is required -
everything goes on in a pair of very large BGA processors, one of which is
the data processing engine, and the other of which is the graphics
processing engine. It is they which make use of the 12v, and they which
gobble the amps from it ...

The power supply does have other outputs, but these are all at very low
current availabilities, so will be for support logic and maybe some core
supplies for the two processors. Trust me when I say that the two big chips
is where all the power is going, and generating heat that needs shifting
:-)

Arfa

"Jeff Liebermann" wrote in message
...
On Sat, 28 Aug 2010 02:04:07 +0100, "Arfa Daily"
wrote:

Thanks for the insights Jeff.

There was quite a bit of "Learn By Destroying(tm)" involved. Measuring
flatness and thermal resistance were a major exercise, but settled all
kinds of lab arguments.

Incidentally, you might be interested in how Arctic Silver works.
http://www.arcticsilver.com/products.htm
http://www.arcticsilver.com/msds.htm
Silver has a much higher thermal conductivity (410 W/m*K) as compared
to zinc oxide (21 W/m*K) and aluminum oxide (30 W/m*K) which is what's
in common thermal compound.
http://en.wikipedia.org/wiki/List_of_thermal_conductivities
However, if your shove an ohms-guesser into a puddle of Arctic Silver,
it's not conductive. That's because the particles of silver are so
far and few, that the bulk of the solution is polyolester or mineral
oil, which insulates the particles from each other, preventing mutual
contact. However, if you tear apart a CPU/heatsink that's been used
for a while, you'll notice that the Arctic Silver is a thick and dense
paste which is conductive. What has happened is that the polyol ester
mixture has evaporated sufficiently to provide contact between
particles. Since thermal conductivity is best through the silver
particles, the result is a superior thermal connection, with the
sliver particles filling the voids. You could do the same thing with
silver dust, but it would difficult to handle and apply. Meanwhile,
ordinary silicon grease does the same thing, but there's a difference.
The oil does not evaporate as easily, and the ceramic particles are
much larger and less compressible than the silver particles. Fewer
points of contact and lower thermal conductivity of ceramic, means a
worse thermal connection.

All interesting stuff. These are dedicated
games machines, not based on a PC in any way. The power supply is specced
to
deliver 12v at 23 amps, yes, that's twenty three amps ...

Almost all of this is potentially going into these two processors, so not
far off 300 watts between them. No mean task shifting the heat off them !

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core). I had an Alpha CPU machine to play with for a while, which
would burn my hand from the hot air coming out the back.

If you have a power line wattmeter or a Kill-A-Watt meter, I think a
measurement would be helpful.

--
Jeff Liebermann


Again, more interesting stuff Jeff. As to the power consumption of these
chips, see my reply to Jim above. Also, it is split between two chips, it's
actually not quite as much as 300 watts, and will of course be an 'on
demand' thing, depending on how hard the chips are being asked to work by
the processing task that's happening at the time, so the 23 amps is only a
worst case potential input current. However, that said, these two chips do
produce *very* considerable heat even when idling to produce nothing more
than the splash screen.

Arfa

"Arfa Daily" wrote in
news:O24eo.36157$r24.2988@hurricane:

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty
three amps ...

Almost all of this is potentially going into these two processors,
so not far off 300 watts between them. No mean task shifting the
heat off them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box
/ Playstation type boxes. Apart from some support circuitry in IC form
- which admittedly does gobble enough power to make it run hot enough
that a degree of heatsinking to the pcb shielding via thermal pads is
required - everything goes on in a pair of very large BGA processors,
one of which is the data processing engine, and the other of which is
the graphics processing engine. It is they which make use of the 12v,
and they which gobble the amps from it ...

The power supply does have other outputs, but these are all at very
low current availabilities, so will be for support logic and maybe
some core supplies for the two processors. Trust me when I say that
the two big chips is where all the power is going, and generating heat
that needs shifting
:-)

Arfa



Odd that BGA processors are using 12V instead of logic level voltages.

I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Jim Yanik
jyanik
at
localnet
dot com

Jim Yanik wrote:

Odd that BGA processors are using 12V instead of logic level voltages.


Then they would need around 100A at 3.3 volts. The voltage drop
would be a big problem. I'm sure there is a DC to DC converter near the
chip, like used on computer motherboards.


I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

On Fri, 27 Aug 2010 21:18:05 -0500, Jim Yanik wrote:

"Arfa Daily" wrote in
news:dgZdo.79946$Pa3.38201@hurricane:



"Jeff Liebermann" wrote in message
...
On Fri, 27 Aug 2010 01:27:14 +0100, "Arfa Daily"
wrote:

Anyone
else got any constructive comments on the subject of thermal
interfacing of
coolers to high power chips ?

In a past life, I used to design HF SSB marine radios. The typical
transmitter was Class AB 150 watts with about 30% efficiency. That's
two devices, dissipating about 125 watts each, over an area of about
70 sq-cm. Oh yes, no fan allowed.

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical. In the process of getting it to
work, I learned a few things.

1. The less silicon grease used, the better. The idea behind silicon
grease is to fill in the gaps, scratches, and gouges in the power
transistor base and aluminum heat sink. Cross sectional
microphotographs show metal to metal contact on the peaks, but huge
gaps, filled with silicon grease, in between. Under ideal
circumstances, maximum metal to metal contact, with minimum gaps is
the target practice.

2. All heat sinks and transistor bases are NOT flat. I made a
dramatic improvement to the measured thermal resistance by polishing
flat the base of the xsistor and the face of the heat sink. That
meant removing the gold from the copper base, but that's what was
necessary. I used a Moire pattern to measure flatness. A mirror
finish was best, but difficult to achieve. To prevent corrosion, I
plated the exposed copper with electroless tin or silver. For the
aluminum heat sink, I just used abrasive polish and a glass polishing
plate to obtain a mirror finish and flat surface.

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum. Compression
adjusts for the bends, and also provides some level of galling to
provide metal to metal contact. If done correctly, adding silicon
grease actually increases the thermal resistance. However, this is
difficult to do with a CPU that has components on the bottom side,
thus preventing compression. Applying pressure only on the top center
of the CPU, will cause the substrate to bend, and eventually break. I
have some ideas, but nothing that can be retrofitted to an existing
motherboard and CPU socket. This is close, but not optimum:
http://www.frostytech.com/articleview.cfm?articleID=2273 Note the
comments on base finish and flatness.

So, if you want the best head sinking, polish flat the CPU top
(removing all the laser scribbled markings, polish the heat sink face,
use very very very very little silicon grease, and compress the
sandwich until it nearly breaks the CPU.

--
Jeff Liebermann


Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty three
amps ...

Almost all of this is potentially going into these two processors, so
not far off 300 watts between them. No mean task shifting the heat off
them !

Arfa



what processors(microprocessors?) run at 12V? ISTR that today's uPs run
mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

Most run at 12. The core at 1.6. Both AMD and Intel boards have a 4 pin
Molex plug near the CPU for direct 12v from the PSU.



--
Live Fast, Die Young and Leave a Pretty Corpse

"Jim Yanik" wrote in message
4...
"Arfa Daily" wrote in
news:O24eo.36157$r24.2988@hurricane:

Thanks for the insights Jeff. All interesting stuff. These are
dedicated games machines, not based on a PC in any way. The power
supply is specced to deliver 12v at 23 amps, yes, that's twenty
three amps ...

Almost all of this is potentially going into these two processors,
so not far off 300 watts between them. No mean task shifting the
heat off them !

Arfa



what processors(microprocessors?) run at 12V?
ISTR that today's uPs run mostly on 3.3V

Most other digital logic runs at 5V,I believe.

I think you wil find that most of your power is going into the video
drive (or LCD backlight) circuitry.

--
Jim Yanik


Er no. There are no backlights. Or display processor. These are X-Box
/ Playstation type boxes. Apart from some support circuitry in IC form
- which admittedly does gobble enough power to make it run hot enough
that a degree of heatsinking to the pcb shielding via thermal pads is
required - everything goes on in a pair of very large BGA processors,
one of which is the data processing engine, and the other of which is
the graphics processing engine. It is they which make use of the 12v,
and they which gobble the amps from it ...

The power supply does have other outputs, but these are all at very
low current availabilities, so will be for support logic and maybe
some core supplies for the two processors. Trust me when I say that
the two big chips is where all the power is going, and generating heat
that needs shifting
:-)

Arfa



Odd that BGA processors are using 12V instead of logic level voltages.

I'm surprised they don't use some sort of liquid or heat-pipe plumbing to
remove all that heat. Wasn't it the CRAYs that used liquid Freon to flood
the processor cabinet to dissipate al the heat built up?

--
Jim Yanik


Yes, I was amazed when I read the PSU specs. One of the versions is actually
specced 12v at 32 amps !! The PSU plugs directly onto the board via a pair
of brass pins as thick as those on a power cord for a kettle. The heat is
removed via a pair of flat plates that are connected to a network of sealed
copper pipes, a bit like you see on some Technics amps. I've no idea what is
inside those pipes. This whole assembly is cooled by a centrifugal fan that
idles at a very low speed. The heatsinks have to get up to blisteringly hot
before the processor thinks that it might be a good idea to ramp up the
speed of the fan a bit. I guess they have done this to try and keep the
thing quiet, but personally, I think it is a really poor bit of design. I am
looking at ways to make the fan idle faster, without compromising the auto
ramp up beyond that, when the processor deems it necessary, but
unfortunately, it's not quite as easy as a simple 'analogue OR' function,
because the fan is controlled digitally. It is supplied with a constant 12v,
but a third wire has a PWM signal placed on it by the CPU, and the fan's
internal electronics respond to that to control the speed.

Yes, it was the Cray. It had a central octagonal bus backplane as I recall.
The met office here in the UK used to use one for weather data number
crunching, but I think it has been replaced now.

Arfa

"Michael A. Terrell" wrote in message
m...

Jim Yanik wrote:

Odd that BGA processors are using 12V instead of logic level voltages.


Then they would need around 100A at 3.3 volts. The voltage drop
would be a big problem. I'm sure there is a DC to DC converter near the
chip, like used on computer motherboards.

Yes indeed Michael. There are in fact 6 of them. Three on each side of the
board ...

Arfa

On Fri, 27 Aug 2010 20:19:44 -0700 Jeff Liebermann
wrote in Message id: :

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core).

Check again.
http://ark.intel.com/Product.aspx?id...ec-codes=SLBMX

185W! Gotta love that price as well.

On Mon, 30 Aug 2010 05:35:00 -0400, JW wrote:

On Fri, 27 Aug 2010 20:19:44 -0700 Jeff Liebermann
wrote in Message id: :

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core).

Check again.
http://ark.intel.com/Product.aspx?id...ec-codes=SLBMX
185W! Gotta love that price as well.

I stand corrected.
http://techreport.com/discussions.x/18445
Some of the reader comments are rather interesting. Still, with any
of these "powerful" processors, a conventional air cooled machine is
going to have a very hot breath and a rather large power supply. I
just don't see this kind of power dissipation in a "dedicated game
machine". Measuring the AC mains power consumption should settle the
matter.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Aug 27, 6:09*am, Meat Plow wrote:
snip
You answered your own question. The AMD heatsink / quad core Phenom
II 955
Black Edition package comes with Artic Silver already applied. I'm
using
an Antec server case that has a hole and tube in the side cover.
The end
of the tube fits directly over the CPU heat sink so it draws air
directly
from the outside. In back is a pair of 120mm fans controlled by the
mainboard. If the CPU temp goes up all three fans increase
according to
the temp. Or you can set them to run at full speed all the time.
The 650
watt PSU also has a temp sensing 120mm fan. So the box is really
quiet
most of the time. But when rendering video and the CPU usage hovers
around 50% fan speed increases slightly. Video rendering with an
application that takes advantage of multi-core processors seem to
use the
most CPU percentage. I've never seen it go over 50%. Most of the
time it
doesn't go over 10%. *

--
Live Fast, Die Young and Leave a Pretty Corpse

Sony Vegas software will push your processor usage up to nearly 100%
and stay there for minutes. My Phenom II 955 machine normally idles
115-120 Watts but will peak about 100 more while Vegas is rendering a
file. I'm almost tempted to try a 6 core processor to see what
happens.

G²

On Mon, 30 Aug 2010 10:29:52 -0700, stratus46 wrote:

On Aug 27, 6:09Â*am, Meat Plow wrote: snip
You answered your own question. The AMD heatsink / quad core Phenom
II 955
Black Edition package comes with Artic Silver already applied. I'm
using
an Antec server case that has a hole and tube in the side cover.
The end
of the tube fits directly over the CPU heat sink so it draws air
directly
from the outside. In back is a pair of 120mm fans controlled by the
mainboard. If the CPU temp goes up all three fans increase
according to
the temp. Or you can set them to run at full speed all the time.
The 650
watt PSU also has a temp sensing 120mm fan. So the box is really
quiet
most of the time. But when rendering video and the CPU usage hovers
around 50% fan speed increases slightly. Video rendering with an
application that takes advantage of multi-core processors seem to
use the
most CPU percentage. I've never seen it go over 50%. Most of the
time it
doesn't go over 10%.

--
Live Fast, Die Young and Leave a Pretty Corpse

Sony Vegas software will push your processor usage up to nearly 100% and
stay there for minutes. My Phenom II 955 machine normally idles 115-120
Watts but will peak about 100 more while Vegas is rendering a file. I'm
almost tempted to try a 6 core processor to see what happens.

G²

I use Kino in linux to render raw DV capture. Can't find a suitable linux
app to create dvd containers/structure etc.. in linux so I use a fairly
inexpensive app called DVDtoX from VSO. Fast 10x frame rates on VBR video
encoding usually 2000KB/s. Easy to use nice output. tried Sony DVD
Architect trial, more than I needed. Linux is much more efficient at
processor usage but applications aren't up to par.



--
Live Fast, Die Young and Leave a Pretty Corpse

"Jeff Liebermann" wrote in message
news
On Mon, 30 Aug 2010 05:35:00 -0400, JW wrote:

On Fri, 27 Aug 2010 20:19:44 -0700 Jeff Liebermann
wrote in Message id: :

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core).

Check again.
http://ark.intel.com/Product.aspx?id...ec-codes=SLBMX
185W! Gotta love that price as well.

I stand corrected.
http://techreport.com/discussions.x/18445
Some of the reader comments are rather interesting. Still, with any
of these "powerful" processors, a conventional air cooled machine is
going to have a very hot breath and a rather large power supply. I
just don't see this kind of power dissipation in a "dedicated game
machine". Measuring the AC mains power consumption should settle the
matter.

--
Jeff Liebermann


Have you any idea just how much processing power it takes to run a
user-interactive story in real time, and then to 3D render the graphics in
real time ? Do you think that they rate the 12v PSU for 23.5 amps in one
version, and 32 amps in the other, for fun ? Those are not real questions,
because I know full well when you stop and think about it, you know the
answers, Jeff.

I've just looked at the rating plate on the bottom of one of the cases, and
it is 240v (nominal UK line voltage) at 1.8 amps. I make that a maximum
input power of around 430 watts. It's a switching PSU, so I reckon that we
can rate that as being at the very worst 80% efficient, so that's still 345
watts potentially going somewhere. I'm prepared to go with 45 watts into
ancillary circuitry on the board, which still leaves around 300 watts going
somewhere. Perhaps I'm being naive, but my best guess is that it's
disappearing into the two bloody great BGAs which the manufacturers are
trying their utmost to heatsink. If you try to run one of these machines
with the heatsinking not in place, it goes into thermal protect in about 5
seconds - and all it's doing then is booting. The heatplates on the BGAs are
at this point hot enough to take your fingerprints off ...

Nope, I'm pretty sure that these two puppies are good for 150 watts apiece,
when the machine is doing some real work.

Arfa

"Arfa Daily" wrote in
:



"Jeff Liebermann" wrote in message
news
On Mon, 30 Aug 2010 05:35:00 -0400, JW wrote:

On Fri, 27 Aug 2010 20:19:44 -0700 Jeff Liebermann
wrote in Message id: :

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core).

Check again.
http://ark.intel.com/Product.aspx?id...0&spec-codes=S
LBMX 185W! Gotta love that price as well.

I stand corrected.
http://techreport.com/discussions.x/18445
Some of the reader comments are rather interesting. Still, with any
of these "powerful" processors, a conventional air cooled machine is
going to have a very hot breath and a rather large power supply. I
just don't see this kind of power dissipation in a "dedicated game
machine". Measuring the AC mains power consumption should settle the
matter.

--
Jeff Liebermann


Have you any idea just how much processing power it takes to run a
user-interactive story in real time, and then to 3D render the
graphics in real time ? Do you think that they rate the 12v PSU for
23.5 amps in one version, and 32 amps in the other, for fun ? Those
are not real questions, because I know full well when you stop and
think about it, you know the answers, Jeff.

I've just looked at the rating plate on the bottom of one of the
cases, and it is 240v (nominal UK line voltage) at 1.8 amps. I make
that a maximum input power of around 430 watts. It's a switching PSU,
so I reckon that we can rate that as being at the very worst 80%
efficient, so that's still 345 watts potentially going somewhere. I'm
prepared to go with 45 watts into ancillary circuitry on the board,
which still leaves around 300 watts going somewhere.

that assumes that all the power of the supply is actually used.
I'm sure there is some reserve capacity there.

"max input power" is not "actual used power".

Perhaps I'm being
naive, but my best guess is that it's disappearing into the two bloody
great BGAs which the manufacturers are trying their utmost to
heatsink. If you try to run one of these machines with the heatsinking
not in place, it goes into thermal protect in about 5 seconds - and
all it's doing then is booting. The heatplates on the BGAs are at this
point hot enough to take your fingerprints off ...

Nope, I'm pretty sure that these two puppies are good for 150 watts
apiece, when the machine is doing some real work.

Arfa





--
Jim Yanik
jyanik
at
localnet
dot com

On Tue, 31 Aug 2010 01:26:23 +0100, "Arfa Daily"
wrote:

Have you any idea just how much processing power it takes to run a
user-interactive story in real time, and then to 3D render the graphics in
real time ?

Well, no. I'm not a power user. What little rendering I do is with
bacon fat.

Do you think that they rate the 12v PSU for 23.5 amps in one
version, and 32 amps in the other, for fun ? Those are not real questions,
because I know full well when you stop and think about it, you know the
answers, Jeff.

Actually, I don't know. I don't have any customers with such machines
and have had zero experience with high power graphic workstations
(other than early 1980's Applicon CAD stations) or game machines. I
have worked on various network servers, which do burn such power
levels. I have looked at a 3D MRI image processor, which had some
manner of dedicated processor inside, but it certainly wasn't belching
400 watts of heat (my estimate by the amount of fan noise).

I've just looked at the rating plate on the bottom of one of the cases, and
it is 240v (nominal UK line voltage) at 1.8 amps. I make that a maximum
input power of around 430 watts. It's a switching PSU, so I reckon that we
can rate that as being at the very worst 80% efficient, so that's still 345
watts potentially going somewhere. I'm prepared to go with 45 watts into
ancillary circuitry on the board, which still leaves around 300 watts going
somewhere. Perhaps I'm being naive, but my best guess is that it's
disappearing into the two bloody great BGAs which the manufacturers are
trying their utmost to heatsink. If you try to run one of these machines
with the heatsinking not in place, it goes into thermal protect in about 5
seconds - and all it's doing then is booting. The heatplates on the BGAs are
at this point hot enough to take your fingerprints off ...

Nope, I'm pretty sure that these two puppies are good for 150 watts apiece,
when the machine is doing some real work.

Ok, I stand corrected. I've been assuming that the CPU's are doing
most of the power dissipation. I didn't think of a dedicated graphics
processor or whatever the BGA chips are doing. Do you have a gun
style IR thermometer? I use that to determine if anything is running
hot. I use a black (non-reflective) cardboard tube attached to the
lens to prevent it from picking up adjacent components. Incidentally,
I have yet to find one where the laser dot actually points to where
the device is measuring when in close proximity. You can also get a
rough idea of how much effort is going into cooling. If the BGA's
burn more power than the CPU's, then they're going to need more
massive heat sinks and better air cooling. At 400 watts, I would
think they would have gone to heat pipes and external radiators or
maybe liquid cooling.

Incidentally, I repaired a P4 motherboard yesterday which used Artic
Silver. My guess is that there was about 5 times as much Artic Silver
smeared over the CPU (and down the sides where it does nothing) as
necessary. The stuff down the sides was still fluid, so at $10 for
3.5 grams, I saved the excess.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Tue, 31 Aug 2010 09:35:11 -0700, Jeff Liebermann wrote:

ncidentally, I repaired a P4 motherboard yesterday which used Artic
Silver. My guess is that there was about 5 times as much Artic Silver
smeared over the CPU (and down the sides where it does nothing) as
necessary. The stuff down the sides was still fluid, so at $10 for 3.5
grams, I saved the excess.

Heh...reminds me of a previously repaired (not by me) QSC PLX series amp
I opened up and scraped about a pound of white paste out of it.



--
Live Fast, Die Young and Leave a Pretty Corpse

Hi!

This is quite a bit more dissipation than the average desktop, causing
some things to be more critical.

Well, it used to be. ;-)

The Pentium 4 "Pres-hot" didn't earn that derogatory nickname for nothin'. I
cringe to think of multi-processor systems and how much heat they were
dumping into the air. I had a 3.4GHz Prescott P4 in a Dell Dimension 8300.
On hot days, it had no problem equaling the sound volume of a small canister
vacuum cleaner.

1. The less silicon grease used, the better.

I remember reading that somewhere. I'm not sure that everyone--including
some major manufacturers--got the memo. After removing the STK-2038 II
module from my Techics SA-310 receiver, I found a massive amount of heatsink
compound behind it. Wow.

2. All heat sinks and transistor bases are NOT flat.

Somtimes not by a *long* shot!

3. Compression pressure is important. None of the standard spring
clip CPU heat sink holders come even close to optimum.

Really? I find that extremely surprising, especially as firmly as some of
them hold on. They really do *seem* to be doing a good job.

Sometimes the heatsink compound has established a tight enough bond that the
processor comes out firmly glued to the bottom of the heatsink, without so
much as releasing the ZIF socket lever. I've seen that on Socket 478 and
AM2+ boxen before. It's kind of scary to look down and realize the processor
isn't where it should be!

William

"Jim Yanik" wrote in message
4...
"Arfa Daily" wrote in
:



"Jeff Liebermann" wrote in message
news
On Mon, 30 Aug 2010 05:35:00 -0400, JW wrote:

On Fri, 27 Aug 2010 20:19:44 -0700 Jeff Liebermann
wrote in Message id: :

I don't believe it. The winner of the power hogging consumer CPU
contest was the DEC/Intel Alpha 21364 (EV79):
http://en.wikipedia.org/wiki/Alpha_21364
which burned 155 watts. Itanium II came close with 130 watts (per
core).

Check again.
http://ark.intel.com/Product.aspx?id...0&spec-codes=S
LBMX 185W! Gotta love that price as well.

I stand corrected.
http://techreport.com/discussions.x/18445
Some of the reader comments are rather interesting. Still, with any
of these "powerful" processors, a conventional air cooled machine is
going to have a very hot breath and a rather large power supply. I
just don't see this kind of power dissipation in a "dedicated game
machine". Measuring the AC mains power consumption should settle the
matter.

--
Jeff Liebermann


Have you any idea just how much processing power it takes to run a
user-interactive story in real time, and then to 3D render the
graphics in real time ? Do you think that they rate the 12v PSU for
23.5 amps in one version, and 32 amps in the other, for fun ? Those
are not real questions, because I know full well when you stop and
think about it, you know the answers, Jeff.

I've just looked at the rating plate on the bottom of one of the
cases, and it is 240v (nominal UK line voltage) at 1.8 amps. I make
that a maximum input power of around 430 watts. It's a switching PSU,
so I reckon that we can rate that as being at the very worst 80%
efficient, so that's still 345 watts potentially going somewhere. I'm
prepared to go with 45 watts into ancillary circuitry on the board,
which still leaves around 300 watts going somewhere.

that assumes that all the power of the supply is actually used.
I'm sure there is some reserve capacity there.

"max input power" is not "actual used power".

Well Jim, that was why I used the word "potentially", but judging by the
size of the pins used to couple the power supply's output into the board -
if you've been following the thread, you will recall that I previously
described them as being of the size you would find on the line cord for a
kettle - then I wouldn't say that there was too much in the way of reserve.
Anyway, just think about that premise for a moment. When have you ever known
a manufacturer of a piece of domestic grade electronics, to over-rate any
aspect of it, let alone the power supply, by more than the few percent
required to just about let it scrape by? It's all about cost, and they are
not going to rate the rectifiers and magnetics and filter caps and output
connectors and so on, for any more than they have to, to keep the
manufacturing costs as low as possible ...

Arfa

"Jeff Liebermann" wrote in message
...
On Tue, 31 Aug 2010 01:26:23 +0100, "Arfa Daily"
wrote:

Have you any idea just how much processing power it takes to run a
user-interactive story in real time, and then to 3D render the graphics in
real time ?

Well, no. I'm not a power user. What little rendering I do is with
bacon fat.

Do you think that they rate the 12v PSU for 23.5 amps in one
version, and 32 amps in the other, for fun ? Those are not real questions,
because I know full well when you stop and think about it, you know the
answers, Jeff.

Actually, I don't know. I don't have any customers with such machines
and have had zero experience with high power graphic workstations
(other than early 1980's Applicon CAD stations) or game machines. I
have worked on various network servers, which do burn such power
levels. I have looked at a 3D MRI image processor, which had some
manner of dedicated processor inside, but it certainly wasn't belching
400 watts of heat (my estimate by the amount of fan noise).

I've just looked at the rating plate on the bottom of one of the cases,
and
it is 240v (nominal UK line voltage) at 1.8 amps. I make that a maximum
input power of around 430 watts. It's a switching PSU, so I reckon that we
can rate that as being at the very worst 80% efficient, so that's still
345
watts potentially going somewhere. I'm prepared to go with 45 watts into
ancillary circuitry on the board, which still leaves around 300 watts
going
somewhere. Perhaps I'm being naive, but my best guess is that it's
disappearing into the two bloody great BGAs which the manufacturers are
trying their utmost to heatsink. If you try to run one of these machines
with the heatsinking not in place, it goes into thermal protect in about 5
seconds - and all it's doing then is booting. The heatplates on the BGAs
are
at this point hot enough to take your fingerprints off ...

Nope, I'm pretty sure that these two puppies are good for 150 watts
apiece,
when the machine is doing some real work.

Ok, I stand corrected. I've been assuming that the CPU's are doing
most of the power dissipation. I didn't think of a dedicated graphics
processor or whatever the BGA chips are doing. Do you have a gun
style IR thermometer? I use that to determine if anything is running
hot. I use a black (non-reflective) cardboard tube attached to the
lens to prevent it from picking up adjacent components. Incidentally,
I have yet to find one where the laser dot actually points to where
the device is measuring when in close proximity. You can also get a
rough idea of how much effort is going into cooling. If the BGA's
burn more power than the CPU's, then they're going to need more
massive heat sinks and better air cooling. At 400 watts, I would
think they would have gone to heat pipes and external radiators or
maybe liquid cooling.

Incidentally, I repaired a P4 motherboard yesterday which used Artic
Silver. My guess is that there was about 5 times as much Artic Silver
smeared over the CPU (and down the sides where it does nothing) as
necessary. The stuff down the sides was still fluid, so at $10 for
3.5 grams, I saved the excess.


--
Jeff Liebermann
Skype: JeffLiebermann AE6KS 831-336-2558

All of the processing power is in those two BGAs Jeff. They *are* the
processors. One is a dedicated engine that runs the game (or plays a BluRay
disc), as well as handling all the disc I/O - optical and hard - and
internet / network access. On top of this, it manages all of the
housekeeping tasks, so it's doing a lot of work, especially when it's
actually running a game. Modern games have come a long way since the days of
Doom. Most maintain a highly complex 3D 'reality' in which the game is set,
and the gameplay takes place. Just consider for a moment, the highly complex
calculations that have to go on, to work out how potentially many actions
all at once, interact with the 3D model, and the knock-on effects that these
might have on both the gameplay and the graphical environment. And remember
that this is taking place in real time. The second BGA is a dedicated
graphics engine. Again, consider how these games now look. Most are quite
close to reality, and some scenes would have you hard pressed to tell if you
were looking at a photo, or a piece of virtual reality. Given all that, just
imagine the billions of calculations that are going on, again in real time,
to work out the texturisation and surface rendering of all the visible
objects, and how the light and shadows interact with those objects as they
move within the scene. It really is mind-boggling just how sophisticated all
of this is now. I can recall 25 years ago when I worked on high-end graphics
systems, rendering the famous 3D conch shell image took a dedicated graphics
terminal, hosted by a VAX mainframe, around 20 minutes. That's one image,
not moving. Now think about a moving HD image in an HD background in real
time. That's a LOT of processing power, needing a lot of amps to perform ...

The fan on these things *is* large, as is the heatsinking assembly, and when
the processor finally decides to ramp the fan up, it sounds like a vacuum
cleaner. For this reason, at idle they tend to run it at below what I would
consider a 'sensible' minimum, exacerbating the thermal stresses on the
chips, their (lead-free) soldering, and the board to which they are
attached.

Arfa

On Tue, 31 Aug 2010 16:56:37 +0000 (UTC) Meat Plow
wrote in Message id: :

On Tue, 31 Aug 2010 09:35:11 -0700, Jeff Liebermann wrote:

ncidentally, I repaired a P4 motherboard yesterday which used Artic
Silver. My guess is that there was about 5 times as much Artic Silver
smeared over the CPU (and down the sides where it does nothing) as
necessary. The stuff down the sides was still fluid, so at $10 for 3.5
grams, I saved the excess.

Heh...reminds me of a previously repaired (not by me) QSC PLX series amp
I opened up and scraped about a pound of white paste out of it.

You sure that someone hadn't left their marshmallows in there?

On Wed, 01 Sep 2010 05:29:47 -0400, JW wrote:

On Tue, 31 Aug 2010 16:56:37 +0000 (UTC) Meat Plow
wrote in Message id:
:

On Tue, 31 Aug 2010 09:35:11 -0700, Jeff Liebermann wrote:

ncidentally, I repaired a P4 motherboard yesterday which used Artic
Silver. My guess is that there was about 5 times as much Artic Silver
smeared over the CPU (and down the sides where it does nothing) as
necessary. The stuff down the sides was still fluid, so at $10 for
3.5 grams, I saved the excess.

Heh...reminds me of a previously repaired (not by me) QSC PLX series amp
I opened up and scraped about a pound of white paste out of it.

You sure that someone hadn't left their marshmallows in there?

That's a possibility. The 3402's did get hot enough under full load
to roast them.



--
Live Fast, Die Young and Leave a Pretty Corpse

Arfa Daily wrote:

Well Jim, that was why I used the word "potentially", but judging by the
size of the pins used to couple the power supply's output into the board -
if you've been following the thread, you will recall that I previously
described them as being of the size you would find on the line cord for a
kettle - then I wouldn't say that there was too much in the way of reserve.


"The size you would find on the line cord for a kettle" doesn't have
much meaning in the US.


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

On Wed, 1 Sep 2010 02:40:53 +0100, "Arfa Daily"
wrote:

All of the processing power is in those two BGAs Jeff.
(...)

Thanks for the details. I really don't know anything about such
dedicated game machines. I just assumed that all such machines used
common processors to make development easier.

That's a LOT of processing power, needing a lot of amps to perform ...

I found the Kill-o-watt meter and stuffed it in line with my Dell
Optiplex 960 (E8500 3.2Ghz). 43 watts at idle, 70 watts max when
playing a DVD (not including LCD monitor). Speedfan 4.40 says 31C for
both CPU cores after about an hour. The one large fan is barely
spinning and very quiet (which is why I bought this one). When I set
the fan to run full speed, it's quite loud.

The fan on these things *is* large, as is the heatsinking assembly, and when
the processor finally decides to ramp the fan up, it sounds like a vacuum
cleaner. For this reason, at idle they tend to run it at below what I would
consider a 'sensible' minimum, exacerbating the thermal stresses on the
chips, their (lead-free) soldering, and the board to which they are
attached.

Well, theory suggests that the life of a semiconductor device is
greatly affected by the number of thermal cycles it experiences
(thermal fatigue). I don't know if this also applies to CPU's or
whatever is in those BGA chips (FPGA/GPU?), but might be something
else to worry about. I would guess(tm) that the large aluminum heat
sink would moderate any abrupt changes in temperature, thus making it
less of a concern. However, that might not be the case for the solder
balls supporting the BGA.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Michael A. Terrell" wrote in message
m...

Arfa Daily wrote:

Well Jim, that was why I used the word "potentially", but judging by the
size of the pins used to couple the power supply's output into the
board -
if you've been following the thread, you will recall that I previously
described them as being of the size you would find on the line cord for a
kettle - then I wouldn't say that there was too much in the way of
reserve.


"The size you would find on the line cord for a kettle" doesn't have
much meaning in the US.


--


Why is that ? You have electric kettles in your kitchens - I've used them.
Or don't you call them kettles ?. OK, anyway, if it's a better description,
the size of the round ground pin on a line cord that has a three pin plug.
Is that more meaningful ? 3/16" diameter maybe ? 4mm ?

Arfa

Arfa Daily wrote:

"Michael A. Terrell" ? wrote in message
m...
?
? Arfa Daily wrote:
??
?? Well Jim, that was why I used the word "potentially", but judging by the
?? size of the pins used to couple the power supply's output into the
?? board -
?? if you've been following the thread, you will recall that I previously
?? described them as being of the size you would find on the line cord for a
?? kettle - then I wouldn't say that there was too much in the way of
?? reserve.
?
? "The size you would find on the line cord for a kettle" doesn't have
? much meaning in the US.

Why is that ? You have electric kettles in your kitchens - I've used them.


I've never seen one. Even Coffee pots are rare these days.


Or don't you call them kettles ?. OK, anyway, if it's a better description,
the size of the round ground pin on a line cord that has a three pin plug.
Is that more meaningful ? 3/16" diameter maybe ? 4mm ?


3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
much current do those kettles draw?


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

On Wed, 01 Sep 2010 16:55:34 -0400, Michael A. Terrell wrote:

Arfa Daily wrote:

"Michael A. Terrell" ? wrote in message
m... ?
? Arfa Daily wrote:
??
?? Well Jim, that was why I used the word "potentially", but judging by
the ?? size of the pins used to couple the power supply's output into
the ?? board -
?? if you've been following the thread, you will recall that I
previously ?? described them as being of the size you would find on the
line cord for a ?? kettle - then I wouldn't say that there was too much
in the way of ?? reserve.
?
? "The size you would find on the line cord for a kettle" doesn't have
? much meaning in the US.

Why is that ? You have electric kettles in your kitchens - I've used
them.


I've never seen one. Even Coffee pots are rare these days.


Or don't you call them kettles ?. OK, anyway, if it's a better
description, the size of the round ground pin on a line cord that has a
three pin plug. Is that more meaningful ? 3/16" diameter maybe ? 4mm ?


3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
much current do those kettles draw?

Half what a US kettle would draw?



--
Live Fast, Die Young and Leave a Pretty Corpse

On 9/1/2010 5:15 PM, Meat Plow wrote:
On Wed, 01 Sep 2010 16:55:34 -0400, Michael A. Terrell wrote:

Arfa Daily wrote:

"Michael A. Terrell" ? wrote in message
m... ?
? Arfa Daily wrote:
??
?? Well Jim, that was why I used the word "potentially", but judging by
the ?? size of the pins used to couple the power supply's output into
the ?? board -
?? if you've been following the thread, you will recall that I
previously ?? described them as being of the size you would find on the
line cord for a ?? kettle - then I wouldn't say that there was too much
in the way of ?? reserve.
?
? "The size you would find on the line cord for a kettle" doesn't have
? much meaning in the US.

Why is that ? You have electric kettles in your kitchens - I've used
them.


I've never seen one. Even Coffee pots are rare these days.


Or don't you call them kettles ?. OK, anyway, if it's a better
description, the size of the round ground pin on a line cord that has a
three pin plug. Is that more meaningful ? 3/16" diameter maybe ? 4mm ?


3/16" is between AWG 5& AWG 4. 4 mm is between AWG 7& AWG 6. How
much current do those kettles draw?

Half what a US kettle would draw?



A good British 240Vac kettle will take 3KW, yes 3KW. No waiting 10
minutes for the lousy thing to boil.

JC

"Michael A. Terrell" wrote in message
m...

Arfa Daily wrote:

"Michael A. Terrell" ? wrote in message
m...
?
? Arfa Daily wrote:
??
?? Well Jim, that was why I used the word "potentially", but judging by
the
?? size of the pins used to couple the power supply's output into the
?? board -
?? if you've been following the thread, you will recall that I previously
?? described them as being of the size you would find on the line cord
for a
?? kettle - then I wouldn't say that there was too much in the way of
?? reserve.
?
? "The size you would find on the line cord for a kettle" doesn't have
? much meaning in the US.

Why is that ? You have electric kettles in your kitchens - I've used
them.


I've never seen one. Even Coffee pots are rare these days.


Or don't you call them kettles ?. OK, anyway, if it's a better
description,
the size of the round ground pin on a line cord that has a three pin
plug.
Is that more meaningful ? 3/16" diameter maybe ? 4mm ?


3/16" is between AWG 5 & AWG 4. 4 mm is between AWG 7 & AWG 6. How
much current do those kettles draw?


--

Typical UK kettle is 2 - 3kW so 8 to 12 amps or thereabouts. Now, I'm really
confused that you say that you've never seen one. How do you boil water for
a cup of tea, or a cup of instant coffee ? Whenever I come to Florida, I
stay in a private rental home, and although some have had a kettle that
heats from a ring on the cooker, I'm sure that I have also stayed in homes
that had an electric version. Or maybe I'm mistaken on this ? Perhaps with
your line power at only 110v at a non 3 phase outlet, the current levels are
impractical with an element powerful enough to heat the water in short
order. Here, every home - and I really mean *every home* - has one. It is a
known problem for the electricity grid controllers, when TV ads come on in
the middle of the popular soaps. Short term demand goes through the roof, as
everyone rushes out to make a cup of tea or coffee, at the same time. The
controllers genuinely have to know the advert schedules in the TV
programmes, and factor this into their load shedding operations.

Arfa