On 17/03/11 10:59, Daniel James wrote:
In article , Nix wrote:
... which is thousands of times more than any current motherboard
supports.

Not so. My current server ...

Oops, sorry! I thought I had remembered to qualify that remark to
exclude server boards.

... has a motherboard which, fully populated, supports 384Gb

With what size RAM DIMMs? Can you actually achieve that capacity, today,
at any price? If you have 24 slots (which is not impossible) 24x16GB
DIMMs would do it ... and only cost £10k-£15k.

I can achieve that on my 5 year old server, which has 64 slots. With 8GB
DIMMs it could take 512GB of RAM. I don't know about the cost, but
certainly it falls within the remit of "at any price". At the moment it
has a measly 32GB (which was actually quite a lot 5 years ago) and is
sufficient for our current requirements.


If I change "thousands" to "hundreds" my point still stands -- 256TB is
enough addressing space for today's PCs.

It's plenty, and will be for some time to come. At least to those not
trying to model the Earth's atmosphere, or the stars of the Universe.


There are server-class boxes out there with terabytes of RAM now --
although they are hardly consumer-grade.

Indeed they are not.

I suspect boxes like that will be running several CPUs in separate
address spaces, and so aren't strictly relevant to this discussion ...
but I'd be interested to see the spec of such a machine.

My server is an 8-way Opteron SMP box, so all processors are running in
the same address space, and all able to access the full RAM. Small 4-way
SMP boxes with 8- and 12-core Opterons are not uncommon these days. They
are certainly not in the desktop PC category, but neither are they the
preserve of the HPC community either. The building blocks of HPC maybe,
but single units are affordable by small depts. or even motivated
individuals.

--
Nigel Wade