[TAG] 2c tips: troubleshooting memory

[Tom Brown]

After troubleshooting a Linux file server for the last few days, I have 
a two-cent tip on memory. As a side note, once I fixed my memory 
problem, I discovered I also had a framebuffer issue. Conclusion: if 
your problems appear to be the result of one of two causes, it may 
actually be the result of both.
                               
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If you suspect memory problems (particularly if you added memory to your 
system recently), run a utility such as "memtest-86". It's free, and 
available from www.memtest86.com.  It also comes with SuSE Linux, and 
may accompany other Linux distros as well. The trick here is to run all 
the tests, of which memtest has several. Only one of the tests failed on 
me. The rest were fine. You may also want to run the tests repeatedly 
(i.e., overnight), in case the chips have a heat problem. If you have 
more than one SIMM (the little strip the memory is on), test one SIMM at 
a time, so you can tell for sure which one is bad. Now, if one or more 
SIMMs fail, don't throw anything away just yet. If you have another 
computer that uses the same type of memory, test the SIMMs there, as 
well. As I discovered in my own testing, memory that fails to run in one 
computer, may do just fine in another. The reason is that one 
motherboard may be more tolerant of marginal memory chips than another. 
If you've just upgraded your motherboard, or recently flashed the BIOS, 
double-check the BIOS, to make sure that its settings for memory timing 
are correct for the chips you're using, and aren't too fast.

Tom Brown