Path: utzoo!attcan!uunet!maverick.ksu.ksu.edu!ux1.cso.uiuc.edu!usenet
From: mjw06513@uxa.cso.uiuc.edu (Mary Winters)
Newsgroups: comp.sys.ibm.pc
Subject: Memory Problem: How Best to Diagnose?
Message-ID: <1990Jun28.032323.5496@ux1.cso.uiuc.edu>
Date: 28 Jun 90 03:23:23 GMT
Sender: usenet@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 33

I have an interesting problem with memory SIMMs. I recently upgraded my '386
to 4MB of RAM using 1Mb SIMMs (which replaced 2MB of 256K SIMMs). I regularly
run DESQview '386 and QEMM, and never had any noticeable problems. I also ran
a couple of memory testing programs (the one in CHECKIT, as well as a shareware
one from Brown Bag Software). Neither memory test turned up any errors. I 
assumed my memory was fine.

Today, my copy of Turbo C++ arrived. I was playing around, compiling the sample
code provided, when all of a sudden a memory parity error burst onto the 
screen. I rebooted, tried it again. Same thing. Checking the manuals, I found
out that the IDE makes use of available extended and/or exapnded RAM. It
appears that when the compiler swaps out to expanded RAM, a parity error is
generated. I re-ran the memory tests, but the memory passed. I tried various 
other things, but what finally worked was putting back my old memory SIMMs. 
Now TC++ compiles everything fine, no parity errors.

Clearly, one or more of my 1MB SIMMs is faulty. I'm going to take back the
faulty SIMMs and get new ones, but I'd like to make certain that the 
replacements are in perfect working order. Since both memory test programs
available to me passed the bad SIMMs, I need something more powerful, so that
more of these "hidden" defects don't pop up and byte (pun intended) me later.

What's the best memory testing software for a '386? Why would SIMMs which pass
a "normal" test cause parity errors when TC++ tries to access extended RAM?

Thanks for your assistance.




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