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Guide: Mem Auto, Memtest, and your sanity.

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masterwoot

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Joined
Mar 5, 2004
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Mem Auto, Memtest, and proper ram settings

Most of you prolly know that you should be careful what settings your mobo has for memory. You also know it's best to have matched pairs of ram at the same rated speeds as the processor and mobo. However, sometimes we get a bit hasty....

Here are 2 sticks of ram in an older setup running memtest all night quite happily (9+ hours w/ 8 passes):
memtestpass.JPG


Here is the basic bios settings (ya, I know--tis blazing fast :) )

mem266.JPG


Notice the memory frequency was manually set to 266. Now here's what happened in "auto" mode. Nothing else in the whole system was changed, just the memory frequency is set to "auto."
memauto.JPG


Most of us might think that would be just fine. Here's the results after 8 seconds of memtest (420 errors already):
memtestfail1.JPG


And after 38 seconds of memtest (3628 errors, oh my!):
memtestfail2.JPG


Hmmmm.... I don't think I want to install windows on that setup.

So what happened? The ram was different latencies (CAS 2.5 and CAS 3) and different brands, yet both were rated at PC3200 = 400 mhz for the memory frequency. Ouch. That was too much for this mobo and cpu to handle in "auto" mode.

However, manually setting the cpu frequency to 266 (and checking the memory timings were not in auto also) resulted in a tolerable setup.

MAIN POINT: Be sure your ram settings in the BIOS match the chip and mobo tolerances. This is best tested using memtest.


Don't forget that the best setup is to have a matched pair of ram stix--especially if you'd like to run in dual channel.



Resource: Memtest and all it's doc's can be found here

Resource: Memtest86 ver 3.2 .iso image to burn to CD can be downloaded from here
 
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