Mixing Memory

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After rebuilding the downstairs WinXP machine
(drives etc. onto a new motherboard, installed
RAM is: 2.5 Gb as
512 Mb DDR2-SDRAM (PC2-4200 / 533 MHz)
2 Gb DDR2-SDRAM (PC2-5300 / 667 MHz)

I just found in the parts box a RAM unit of
512 Mb PC400.

1. Would there be any benefit in adding this
to the PC?

2. How about the difference in RAM speeds
listed above? I wonder if, the way I use this PC,
it would run faster with only 2 Gb of faster
ram than with the 512 Gb unit as well?
(When running with only 512 Gb pending
other reinstallations, PAGEFILE.SYS got no
bigger than 1.6 Gb.)

(PS: the other recent query about error
messages at boot conncerns the upstairs PC.)
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

Re: Mixing Memory

Don Phillipson wrote:
Quoted text here. Click to load it

Well, the first question is, are the two memory types the same ?

With all power removed, if you try to fit the RAM from the parts
box, does it fit ? Does the slot line up ? It almost sounds
to me, like it might be a different type and not compatible.

Whether the current config is good, might depend on whether
the chipset is dual channel or not. If the motherboard was
a single channel setup, then mixing 2.0 + 0.5 GB on the same
bus, makes no difference. If you're using dual channel,
then the memory may run a bit slower, or part of the memory
space, will be a bit faster than the remainder of the memory
space. If it really is a dual channel system, it would be better
to match pairs of DIMMs. If you owned a 2GB DIMM, and had dual
channel, you'd pick up a second 2GB stick. And preferably,
match the speed and timing a bit closer. With the combo you
have now, the slow stick (512MB PC2-4200) is setting the
speed for the system. If you could match with at least a PC2-5300
stick, then you could run at that speed. As long as the chipset
has an option in the BIOS to go that fast.

In the grand scheme of things, it probably doesn't make that much
difference. It all depends how well the processor cache,
hides the memory performance.

And the difference between a system with 2.5GB of RAM and 3.0GB
of RAM, is so small, it's not like this is going to make the OS
that much faster. It'll feel relatively the same. If you went from
having only 512MB to 2.5GB, you'd probably notice that. Especially
if the OS was Vista or Windows 7, as they need the RAM. They're

If you ever get to test Windows 8, it's amazing. It has a much reduced
diet. I tested the preview, in a virtual machine, and that OS preview
could run in 128MB of RAM. Simply amazing, compared to the others.
Probably by the time it's released, the minimum will be a bit higher
than that. But it's looking good so far. I'm not overjoyed about
the interface, but the memory consumption was a shocker. The worst
part of Windows 8 from a hardware perspective, is it doesn't print
nice BSODs on the screen. Many times, when I had problems, I was
facing a perfectly black screen. Not good, as a form of feedback.
Bring back the blue screen... Print garbage on my screen. I find
that a bit more comforting. Feels like a computer, when there
is a blue screen with hex to look at.


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