Re: A78nx deluxe-- can it use high-density memory?

Darren Garrison wrote:
> I'm getting lots of BSODs lately, where the message is "driver irql not less or
> equal". I'm thinking that maybe my memory is going bad. For years, when I
> boot, my talking BIOS has been saying "computer failed memory test". I
> currently have a pair of Corsair (I bought high end, and look where it got me)
> DDR 333 (PC2700) 512 MB, but it can run DDR 400 (PC3200). I see on pricewatch a
> pair of 1 GB PC3200 can be picked up for less than 30 bucks, but they are high
> density.

Ebay is full of the high density stuff. The adverts on Ebay usually include a chipset
list. Nforce2 is not included. Neither are many Intel chipsets. (And even though
they list Intel 915 in this particular list, if you download Intel datasheets
for their chipsets, they don't generally approve or recommend x4 memory. The
datasheets mention x8 or x16 chips instead.)

*******
(High density) Known to work with:

VIA P4X266A
VIA KT266/333 (except ASUS KT266/333)
VIA KT600 (except ASUS KT600)
VIA PT800
SIS 645
SIS 648
648FX
SIS 746FX
KM400
K8T800
KT 880
KT 400 (except ASUS KT400)
KT 400A
SIS 661FX
SIS 655
SIS 650GX
SIS 650
NFORCE 250GB
ULI CHIPSETS
INTEL 915
NFORCE 4 SLI
VIA APPOLLO P4X400
VIA K8M800
VIA K8M890
VIA K8N800
VIA K8N890
VIA K8T800
VIA K8T890
VIA K8T900
VIA PT800
VIA PT880
VIA PT890
VIA P4M800
VIA P4M800 PRO
VIA P4M890
VIA P4M900
VIA PN800
SIS 648
SIS 649
SIS 650
SIS 651
SIS 656
SIS 661
SIS 748
SIS 750
SIS 755
SIS 756
*******

I would recommend buying 2x1GB of branded memory. I bought some OCZ with a
rebate, and it turned out to work OK. (It took close to three months to
get the rebate.)

The memory that works, would be double sided and have (16) 64Mx8 chips.
Such a 1GB PC3200 module would be fully detected by Nforce2 chipset,
and would also work with DDR Intel chipsets. Branded RAM generally
works with everything. Ebay RAM doesn't.

The Ebay stuff would be (16) 128Mx4. And even in cases "known to work with",
we don't know if one, two, or three sticks would work. Mushkin used to have
a test page, where they listed some of their in-house test results, and their
claim was that only one motherboard they tested, could be filled full of
the high density sticks and still work. (Sadly, they've removed that
section of the website, and web.archive.org could not archive it.)

I have heard of problems with more than 2GB total memory on Nforce2,
but don't know if the issue is motherboard specific or affects
all motherboards. So if going above 2GB total, I'd at least try
looking in a few forums first, for evidence it works. Nforcershq
used to have lots of that kind of info.

http://www.nforcershq.com/forum/search.php

If you're going with just 2x1GB total, there is less to worry about.
Just the usual issues about the chipset being marginal when running
at DDR400, is the only real issue that stands out. (My cheap RAM
wouldn't work at DDR400 on Nforce2, so years ago I had to buy CAS2
memory to make it work well at DDR400. Other people did manage
to get their CAS3 RAM to work.)

With regard to "computer failed memory test", be aware that the
voice message is based purely on a timer in the Winbond chip.
The idea is, if the memory test BIOS code completes in time,
the BIOS code clears the timer, and the customer doesn't get a
voice message. If the memory test fails (such as the memory test
BIOS code actually crashes), the timer trips and the vocal message
is delivered. When this clever scheme screws up, is if someone at
Asus sets the time constant too short, for the memory test to complete
in time and clear the timer. Some people even used to hear multiple
vocal post error messages, because of issues like that.

You should use -

1) memtest86+ from memtest.org . It tests nearly all the memory
(except for 1 MB or less reserved by the BIOS itself). It does
a good job of detecting "stuck at" faults. Versions are available
in the form of a boot floppy or bootable CDROM. My Knoppix CD
also supports running it by typing "memtest" at the boot prompt.
(Version 1.65 is part of that CD.)

2) Running Prime95 from mersenne.org in Torture Test mode, covers
actual operating conditions. You should be able to run for
hours, without the program stopping. You boot Windows (or Linux)
and run Prime95. You don't have to "join GIMPs" to do a Torture
Test. The test does a mathematical calculation, with plenty of
memory operations. For example, if I run it right now on my 2GB
sized machine, it allocates 1600MB for the test. I've used that
to find "weak" areas in memory, that are subject to random failures.
The reason Prime95 is better, is it has a tendency to heat up
components and stress them a bit better.

So run some tests first, to confirm your suspicions.

HTH,
Paul