ram dimm size misreporting

[zebardy]

I have just purchased and installed a 256MB pc100 dimm, however my motherboard reports that the total memory has increaced by only 128MB. Sandra tells me that the dimm reports that it is a 256MB dimm, but then it tells me that the dimm in its slot is only 128MB. I think the dimm is probably knackerd, but I would be grateful if any of you can help.

Thanks

 

[Jakespeare]

You mainboard is suffering from age.

You can install OLD 128 MB modules, but your old
BIOS won't recognize that newer RAM. What you probably
have is 128 MB modules with RAM chips on BOTH sides.
The NEW CHIPS..... the 256 MB modules have RAM on both
sides,,,,, but the modules are a different configuration.
It isn't the amount of RAM total that counts here,
but the fact that the modules have a different density
than the OLD RAM. RAM was made with the modules
having less RAM in each module several years ago.
For example, a 32 MB module would have 8 chips.
Now, a 128 MB module will have 8 chips on one side,
with each RAM module having 16 MB's per each module.
Now, and old 128 MB module would have likely had
16 - 8 MB modules, or 16x8 = 128.

I suspect that you have a 256 MODULE that is 16x16 = 256.
Those 16 MB modules are not being recognized.
Or, you have a double sided module that is only reading
ONE SIDE....... you might see that in one of your POST
Screen...... memory in SLOT 0 = 128 MB's and not shown
in SLOT 1 at all.
OR, SLOT 0 = 64 MB & SLOT 1 = 64 MB

You may have RAM that works perfect in a new board,
but quite simply, only HALF of the Memory will be
seen by an OLD BIOS.
I have seen the exact same thing on older boards.
Occassionaly, but not all the time, flashing the BIOS
will update the capabilities of a mainboard and allow
you to upgrade hardware.

I hope this has cleared up some of the mystery for you.
You can always go on the Internet to get more information.

 

[zebardy]

Thanks Jakespeare for your reply, ive looked at the dimm again and it looks identical to a 128MB dimm, apart from the fact it has chips on both sides. Ill see if i can find a bios update, but its doubtfull as ive been trying to do this for a while anyway. My bios is an award bios, which is now pheonix, and the link from there website leads to another company, from which id have to buy an update, oh well.