On 16/01/2021 07:25, Paul wrote:
Harry Bloomfield wrote:
Acer ES1-521 with 8Gb RAM, AMD A6-6310 CPU, Radeon R4 Graphics1Tb HDD.
It seems to have one memory slot occupied, one empty. Running Win10
64bit.

Uh,oh!

https://www.cpu-world.com/CPUs/Puma/...20A6-6310.html

** Memory channels: 1************* ===
** Channel width (bits): 64
** Supported memory: DDR3L-1866
** DIMMs per channel: 2*********** ===

It's not dual channel, according to that.
This means there is no bandwidth increase
from stuffing the second slot.

All that stuffing the second slot does,
is increase the overall amount of RAM.
For which you have to decide, whether you
were "short" of RAM previously.

The above issue is also a danger with dual channel CPUs.
The designer of the motherboard reserves the right to
only wire up one of the two channels, and put two DIMMs
on that single channel. Doing so, reduces power consumption
on the memory controller, by two or three watts, improving
battery life. Part of that, is things like terminator power
for the bus (the bus design varies from one generation to
the next, so I will refrain from predictions on this).

But the above information suggests that, unless you
really really need to double the RAM, it's just not
worth it. For example, some people like to keep 200 tabs
open on their browser (for work say), and those are the
people who will tell you how wonderful all the extra RAM was.
Well, their processor is now slow as molasses, lugging
all that junk around. As long as the web pages are
not allowed to update themselves, the CPU loading
will be less.


It seems that a range of CPUs were fitted to the E21-521 and that some
had fitted the A8-6410. This is an interesting article where it seem bus
speeds went down after fitting a second module.

https://community.amd.com/t5/process...eed/m-p/404364

Another article said that they really ought to be matching pairs,
including manufacturer, in order to use any dual channel feature,
assuming that is an option for Harry's laptop.