Re: Asus A7V8X-LA not detecting RAM

blackbolek wrote:
Hi,

I've got a little problem with my RAM. My PC (Compaq Presario
SR1309UK) has Asus A7V8X-LA motherboard. I've found specification for
this board and it says that it supports up to 2GB of DDR RAM. I had
only 768MB until recently so I've decided to upgrade and I bought 1GB
of RAM. When it arrived I replaced 256 MB with 1GB (so I should have
1.5 GB). But my computer sees only 512MB in the slot where 1GB is
plugged in. I searched a little and I found that the board supports up
to 2GB but on Compaq web page it says that it only supports 1GB.
Now - I'm not sure if Compaq made any hardware modification for this
motherboard (which resulted in smaller RAM supported) or is it only
Compaq BIOS ?
Does anybody know if I can force somehow this motherboard to support
2GB of RAM?

Thanks for all your help

First, try reversing the order of population. On some older
motherboards, sometimes it makes a difference if the largest
or the smallest module is first. It is a long shot, but it is
worth a try.

I think your problem could be the RAM you bought. I tried to
research on the VIA.com.tw web site, but their available info isn't
helping matters.

To give you another example, the Nforce2 chipset is used with
Athlon processors. It takes up to 1GB per slot. But it won't
take just any module. It uses a module with (16) 64Mx8 chips,
for its total of 1GB of storage. The alternate way to make
a module, is the "Ebay way", as Ebay is filled with modules
made from (16) 128Mx4 chips. The Ebay module is a single rank,
spread over both sides of the module. What happens on Nforce2,
is the Northbridge is missing one address bit, so the high density
module is detected as just 512MB. (Only 1/2 of each memory chip is
addressable, and the other half cannot be addressed by the
chipset.)

If could be, that a similar thing exists with your KM400/KM400A
chipset. But VIA doesn't offer as much quality info as they used
to for their chipsets. At one time, there was some technical detail for
a VIA chipset. But now, just the fluffy info is offered, which
doesn't do anyone any good.

Sites like Crucial.com and Kingston.com, merely mimic the info
sent to them by the motherboard makers. So if the motherboard
makers get the information wrong, then so does everyone else.

So my *guess* is, you bought high density RAM, and the KM400
happens not to like it. And the memory array on the stick is
only half detected and addressable.

If you buy some branded RAM, like Crucial, Kingston, OCZ,
Corsair, Samsung, Micron, basically anyone who puts their
name on the module, then it is probably safe to buy. The
1GB modules on Ebay, the high density ones, don't have a
name on the modules. The seller may mention "Samsung", but
that is in reference to the high density Samsung chips
being used. And that is not the same thing. You want a
brand name stamped on the module PCB itself, as proof that
someone cared to make a quality product.

In terms of official specs, there is nothing wrong with
1GB DDR memory made with (16) 128Mx4 chips. It is approved
by JEDEC. But Intel does not approve (no Intel desktop chipsets
like x4 chips - x4 chips are normally used on registered modules).
And Intel controls a significant part of the industry. And what
that means in practice, is the Ebay modules should not be for
sale. Only modules that work in *all* motherboards (that support
that size of module) should be offered for sale. Modules which
are $20 cheaper, but only work in half the motherboards,
should not be manufactured. The reason the module does not
have a brand, is because the maker does not want to get
caught.

If you look at item 350082595628 on Ebay.com , there is a list
of chipsets the memory is supposed to work with. KM400 is
listed as working with the high density DIMM. So I hope my
supposition above is wrong, and simply reversing the order
of the DIMMs, will fix this...

Good luck,
Paul
.

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