Motherboard only recognizes 128 of my new 512MB SDRAM

  • Thread starter Thread starter Kris
  • Start date Start date
K

Kris

Hello,

I went through related messages in this group, but couldn't find the
answer yet. Any help is very welcome!

Here's my problem:
I have a VIA® Apollo Pro133 chipset (mobo model 693-686A), with
following characteristics mentioned in the manual:
• A total of three 168-pin DIMM sockets (3.3V SDRAM types).
• Memory size up to 768M Byte.
• Supports SDRAM at 66/100/133MHz.
• Supports Symmetrical and Asymmetrical DRAM addressing.
• Banks of different DRAM types and depths can be mixed.

Up until now, there was 2x32MB of RAM. I bought a 512MB SDRAM stick
and added it to my system. Unfortunately, it only recognized 128 of
the 512MB (so a total of 192MB; this is what the BIOS startup tells
me). Even if I removed the old sticks and put only the new one in
socket #0, I had 128MB of memory. I could accept the machine
recognizing 256 (because it supports up to 768MB in 3 sockets), but
128MB seems very weird.

This is (part of) what the CPU-Z program (system analyzer) tells me
about my system:
Module 0 SDRAM PC133 - 512 MBytes
Module 1 Winbond Electronic SDRAM PC100 - 32 MBytes
Module 2 Winbond Electronic SDRAM PC100 - 32 MBytes

Where do things go wrong?
 
Your problem most likely lies within the density of the memory chips on the
actual DIMM. First of all, you are correct that each slot will only take
256MB modules. So, right there you know you aren't going to use all of the
512MB stick. However, the density of the actual chips also makes a
difference. Either way, if you want to make sure to get the correct
memory, Crucial has a motherboard selector (www.crucial.com) which they
guarantee so that you buy the correct memory.

Good luck,

Mike
 
Mike Mastro said:
Your problem most likely lies within the density of the memory chips on the
actual DIMM. First of all, you are correct that each slot will only take
256MB modules. So, right there you know you aren't going to use all of the
512MB stick. However, the density of the actual chips also makes a
difference. Either way, if you want to make sure to get the correct
memory, Crucial has a motherboard selector (www.crucial.com) which they
guarantee so that you buy the correct memory.
Click to expand...

Thanks for this link, but I already searched a lot of sites to find
info about my mobo, but (as on crucial.com) it is not listed anymore.
How can I find out information on the density of my memory and about
the maximum density supported by my mobo? Are there any tools?
 
Do you know the make and model of your mobo? If so, what is it? If it
can handle up to 256MB per DIMM slot, it can't be that old. We should
be able to find information about it somewhere.
 
Thanks for this link, but I already searched a lot of sites to find
info about my mobo, but (as on crucial.com) it is not listed anymore.
How can I find out information on the density of my memory and about
the maximum density supported by my mobo? Are there any tools?
Click to expand...

The memory density support is determined by the northbridge. The
Apollo133 your board has is different from the Apollo Pro133A, in that
it only supports low-density, 256MB per slot. The correct 256MB
modules your motherboard can use would have 16 chips, 8 per side.
There was a short period when PC133 memory was sold in this
configuration but mostly today you'll find these sold as PC100, often
listed as "16x8", not "32x4". These modules can be near twice as
expensive and are getting harder and harder to find... it might be as
time & cost effective to replace the motherboard, or depending on the
CPU & the use of the system, maybe even the whole set,
CPU/Motherboard/Memory replacement.



Dave
 
Thanks for pointing that out, Kony. I forgot that Kris posted the chipset
in the earlier post.
I was thinking of the mobo manufactuer and then I was going to check their
system documentation.
I didn't think about the fact that all I needed to do was get the specs on
the northbridge chipset.
 
Cannot remember what chipset was then in question but I recall reading that
if all *three* DIMM slots are occupied then the BIOS will divide the caching
by three, otherwise it does not. Might be worth vacating/removing the
2x32MBs to see if the BIOS will at least recognise the 512 as 256 in slot 0.

Keith
 
John Smith said:
Cannot remember what chipset was then in question but I recall reading that
if all *three* DIMM slots are occupied then the BIOS will divide the caching
by three, otherwise it does not. Might be worth vacating/removing the
2x32MBs to see if the BIOS will at least recognise the 512 as 256 in slot 0.

Keith
Click to expand...


I already tried that one: there is still only 128MB recognized :-(
 
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