Is this a sign of memory going bad?

[Chris Dillon]

On Thu, 25 Nov 2004, Chuck Robey wrote:

> I don't want to embarrass anyone here, but something needs to be 
> said. Note this next sentence carefully: THERE IS NO SUCH THING AS A 
> WORKING MEMORY TEST PROGRAM!!!
>
> Anyone who tells you otherwise is no friend of yours, because they 
> are making your life hard.  It's very alluring to assume that 
> programs written to do a job actually do that job, and most 
> especially in the case of memory test, one would *really* **REALLY** 
> wish that Chuck here was lying, cause you honestly need a memory 
> test program, but the truth is otherwise: memory test programs don't 
> work.  At the very best, if they spend 30 minutes carefully 
> exercising memory, you get a factor that is maybe 10% reliable, and 
> 90% wishful guessing.
>
> With that in mind, sometimes, the very best memory test programs can 
> give you better ideas that memory you thought was failing IS 
> failing.  The opposite, proving that memory is good, is just 
> totally, totally useless, you cannot take any data home at all about 
> your memory being good.

The memory-test programs are not entirely worthless.  Just recently we 
had a lab of PCs where some of them would go wonky and randomly lock 
up hard.  This was happening for months and we couldn't put our finger 
on the problem.  We thought maybe it was something in our Windows 
build, so we tried booting Microsoft's stand-alone memory tester (yes, 
they have one, and I'm not sure where I got it, MSDN perhaps?), very 
similar to memtest86.  After a random number of test passes, sometimes 
100+ passes (many hours, overnight), some of the machines would lock 
up.  No errors indicated, they just froze.  Oops.  Definately NOT a 
software problem.  After fiddling around with some of the 
clock/voltage related BIOS settings, putting new thermal compound 
between the CPUs and heatsinks, reseating cards and memory, placing 
the PCs inside a hexagram drawn on the floor and dancing nak... 
nevermind... we got them to run the tests continuously through our 
entire 4-day Thanksgiving weekend without problems.  For the last 4 
days (including today), we haven't had any problems with them.

So, these memtest programs can at least be valuable stress-testing 
tools but be prepared to run them for hours or days at a time before 
they will catch something. :-)

-- 
  Chris Dillon - cdillon(at)wolves.k12.mo.us
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Q: Because it reverses the logical flow of conversation.
A: Why is putting a reply at the top of the message frowned upon?