[ltp] memory problems ?

[Fabrice Bellet]

Hi,

I suspect memory problems on my T40. I only have linux on my machine, so 
I can just rely on the symptoms I see on this OS, and on the information 
provided by memory testers.

I added a supplementary 512MB module to the builtin 512MB configuration,
purchased at IBM, FRU 10K0033. According to IBM, this module is 
correctly supported on my machine :

http://www-3.ibm.com/pc/support/site.wss/MIGR-41751.html?doctype=

Since the beginning, I noticed random memory problems with Linux 
(unreproductible gcc internal error, sig 11, rare kernel crashes).
All these glitches let me suppose that I have a problem with my memory 
chips.

I tested the memory with the shipped Pc-Doctor program, and no problem 
was reported.

I patched memtest86 to detect the cache configuration of the pentium M,
and I could use memtest86 too to test the memory. Without surprise, 
it discovered some errors, on test 3 and test 4, all failing address 
locations were above 512MB. Similar errors were found in both battery 
(600MHz CPU) and AC power mode (full speed CPU). The errors disappeared 
when running  memtest86 with only the 512MB built-in module (three full
passes were successful).

This additionnaly memory module is stamped with an IBM sticker, and memory 
chipsets come from Micron (P/N MT16VDDS6464HG-265). So these modules are 
supposed reliable.

Spec sheet here :
http://download.micron.com/pdf/datasheets/modules/DDS16C64x64HG_B.pdf

Anyone with similar experience with these 512 modules ? Should I suspect 
an overheat problem as the back location of the extra memory chip is 
supposedly less well air cooled ? 
-- 
fabrice