Is it safe to use mixed speed memory?

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I have been using the following memory for over 12 months:

2 x PC3200 DDR400 512MB CL3  16chip
Hynix HYMD264646D8J-D43 AA-M

2 x PC3200 DDR400 512MB CL2.5 16 chip

I make sure that they are used in pairs in the same colour slots

Recently I have been getting BSOD and presently I'm trying memtest to see if
one of the sticks is faulty.   However all four will run without problem on
their own or with their matched companion.

Motherboard is a ECS KN1 SLI Extreme



Re: Is it safe to use mixed speed memory?

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Yes, it is safe. In your example, all the memory will be
running at CAS 3. At least, if you allow the BIOS to set
the memory clock and timing automatically.

You can use memtest86+ from . It is a self-booting
test program, and will boot from a floppy or a CD.

Start by testing all four sticks. Allow at least two full passes
with memtest86+. When you quit the program, the computer will
start to reboot. Either remove the media, or change the boot
order, to boot from Windows again. No errors are acceptable.

If you detect a failure, you can repeat the testing, by using
just one stick of memory at a time.

I've bought two sets of cheap (generic, unbranded) memory locally,
when it was on sale. The memory developed defects, about 1.5 years
after purchase. The warranty was no longer valid in one case,
and in the other case, the local company was out of business.

So it is possible for memory to fail while you are using it.
I've also heard of motherboards that seem to be able to damage
memory (a set of memory only lasts about three months, and yet
Vdimm is not set too high).

If memtest86+ seems to be passing error free, no matter what
combination of memory you use, you can try Prime95 and see if
it reports errors. No errors are acceptable in Prime95.
(During its operation, select "Torture Test" when prompted.)
This version is for Windows, and a Linux version is also available.
It will run until you stop it and exit. Four hours of operation
without any errors, is a good result.


Re: Is it safe to use mixed speed memory?

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Great information.  I will try this.



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