In article , fred wrote:

A7N8X-VM/400 - it's official, Asus' most memory fussy mobo

Careful when using this mobo with integrated graphics (which was probably
why you wanted to buy it). Memory timings when system memory is
shared with the integrated graphics processor are far tighter than when a
plugin agp card is used.

I'm running cheap & cheerful 400MHz ram at 333MHz and figured the
underclocking would leave me a healthy timing margin. It does, 24hrs of
memtest86 and 12hrs of Prime95 suggest it's solid, but run anything
graphics intensive, like a movie, and it falls flat on it's face. Symptoms are
typical of interaction between graphics & system accesses, corrupted
stripes in the display, then the inevitable crash as a crucial area of system
mem is corrupted. Ok, I've got cheap memory, but use a plugin agp card
and it's solid as a rock - seems a little unfair.

Asus uk tech support are patient & helpful, but basically they say go &
buy premium memory, which memory you ask, as there is currently no
approved memory list for this board. He suggests I visit my friendly local
retailer and try premium memory brands until I find one that works.

After a long call (friday afternoon) the support guy's resolve falters; he
says:

1. This board was never intended for public sale
2. It was produced at the request of large OEMs to satisfy the need for
simple, fully integrated boxes.
3. It is their most memory fussy board ever.
4. When the pet OEMs ran into memory problems they were asked which
memory they would like to use and the board/bios was tweaked to suit.
5. There is no publicly available list of the memory that this board has been
tweaked to work with.
6. A user tweakable bios is not in the pipeline for this board

I'm not prepared to take the risk of buying more memory without a
guaranteed fix so I'm using the known fix of a plugin agp card. It is now
solid, cheap memory and all.

Thought I'd make life simple this time, pay the premium, buy the big name
and go for integrated graphics, I won't be making that mistake again.

Strings I found in the 1001 BIOS. The same strings are in the 1002 BIOS.
I don't see anything to suggest a PC3200 stick is getting special
treatment, just the -6 (PC2700) sticks listed below. Presumably
other sticks are adjusted according to the contents of their
SPD (for better or worse). You can find these with a hex editor -
I couldn't get AMIBCP to accept the ROM files.

NT5DS16M8AT-6 Nanya 128MB PC2700 DDR
NT256D64S8HA0G-6 Nanya 256MB PC2700 DDR
MPMA82D-68KX3-MAA Kingmax PC2700 memory 128MB
MPMA82D-68KX3-MBA
MPMB62D-68KX3-MAA Kingmax PC2700 memory 256MB
HYS64D32300GU-6 Infineon PC2700 memory 256MB
HYS64D64320GU-6 Infineon PC2700 memory 512MB
NT512D64S8HB1G-6 Nanya 512MB PC2700 DDR

I checked a A7N8X/VM 1009 BIOS and it has the same module part
numbers in it, all except the last one.

This page has a memory table at the bottom. Note this is not for
the VM/400 board and does not imply the same memory would be
"special" in any way. I only mention this if you want to
discuss this table with your Asus tech support guy.

http://usa.asus.com/products/mb/sock...m/overview.htm

Under the circumstances, I think your workaround, an AGP card,
is the right one. Virtually any AGP card will have better
performance than the integrated graphics, and the AGP card
isn't stealing bandwidth from the memory controller, so you'll
get a (very slight) performance boost when doing normal
computing.

As for the rationale for why the board was produced - no OEM
requested this board. Asus just floods the market with every
chipset they can lay their hands on. Chip makers produce reference
motherboard designs, helping to reduce the work that Asus has
to do to bring a board to market. And, if the board or chipset
turns out to be a flop, Asus tries to sell them anyway. In
cases where a design is prematurely withdrawn from the market
(P4S8X), you won't get a swap for another model, to replace
whatever isn't working properly. So, I don't think there
is any "high minded" intent with respect to what boards they
produce.

(For the less than stellar boards, most home users will tire
of returning the boards under warranty and either crush the
board with a hammer or throw it in a dusty corner of the room.
And, the more unscrupulous home users will Ebay the board to
the unsuspecting noob.)

HTH,
Paul