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Suggestion for memory test

Posted: Sun May 30, 2010 8:54 am
by s69
http://home.earthlink.net/~alegr/download/memtest.htm

My company and I have used this memory test for many years. It is the BEST! It has found issues with bad board design that memtest86 and others would not find. When you run it, some notebooks may even overcurrent trip! Intel were so impressed they contacted the author to ask about the source code! There is also a Windows version available which will test more than 4GB (but in my opinion is not as good at finding faults as the DOS version).

The only problem with it is you need to define the parameters carefully. If you specify too much memory to test then it will give errors at the top areas which may be occupied by the BIOS or graphics. Also you often need to skip the first megabyte as some areas can be used by the BIOS even whilst the test is running.

If you have a 3GB system use a command like

memtest 2900 1 /fastdetect /nousblegacy


64 passes are required for complete test. If the test fails in pass 1, always at the same location near the top of memory, then reduce the 2900 figure until it starts to pass. If it passes, then increase the 2900 figure until it starts to fail at the top of memory. In this way you can find the correct top of memory (which will vary from BIOS to BIOS, look at BIOS POST messages and memtest output to see roughly how much memory is available). Once you find the top of memory, you have a VERY good test of memory and system stability. In 30 years, I have not found a better one!

Posted: Tue Jun 01, 2010 4:00 am
by phoenix00
Only catch is that there's no way to tell fdubcd to not load any memory managers. The closest I could get is to select one of the "Defensive Boot" options and pass in the /ignorexmm parameter into memtest.exe

memory.cfg:

Code: Select all

LABEL -
MENU LABEL AleGR Memtest 2.0
TEXT HELP
 A program for testing DRAM (main memory) of PC-compatible computers. Is 
 designed to run on processors with memory cache, and takes into account how
 the system bus, cache and main memory of Pentium and Pentium Pro (Pentium II, 
 III, 4) processors work. "Use Defensive Boot" recommended.
ENDTEXT
LINUX /boot/syslinux/memdisk
INITRD /ubcd/images/fdubcd.img.gz
APPEND raw ubcdcmd=memtest
memory.lst:

Code: Select all

title AleGR Memtest 2.0\nA program for testing DRAM (main memory) of PC-compatible computers. Is\ndesigned to run on processors with memory cache, and takes into account how\nthe system bus, cache and main memory of Pentium and Pentium Pro (Pentium II,\nIII, 4) processors work. "Use Defensive Boot" recommended.
map --mem /ubcd/images/fdubcd.img.gz (fd0)
map --hook
write --offset=15 (fd0)/bin/setargs.bat ubcdcmd=memtest\r\n
chainloader (fd0)+1
rootnoverify (fd0)
ubcd.ini:

Code: Select all

[Memory]
memtest; "memtest.exe /speed /fastdetect /nousblegacy /ignorexmm"; -$$; AleGR Memtest 2.0 (Test RAM)
Nonetheless nice find s69!