256 mb ram showing as 128mb

[starcraftmaster]

hey i got a 133 sd 256mb of ram stick

when i put it in a computer the computer and bois dectecs it as 128mb of ram

i have tryed it on two computers and both say this

so is it bad ram?

[starcraftmaster]

it is not a double sided ram stick

[bonestonne]

no, the single sided 256mb RAM is high density, most computers had issues with that (although somehow just about every Compaq i ever tried worked fine with it).

the RAM is fine, the motherboards just can't read the density.

[starcraftmaster]

so i can make it 256 at all on my computer

[eyeball]

With that motherboard you will not be able to see more than 128Mb per RAM slot it would seem.

[starcraftmaster]

but in one slot i got a 256 mb mb stick with is double sided

[FishBowl]

There may be several reasons for such a module to be recognized falsely:

- mainboard chipset:

for example, i44BX may have three slots, but the center one would not accept double sided architecture

or the inner architecture of the chips requires to be handled as two banks, also not working on the inner slot, nor on one of the outer, with the inner occupied in any way

- module chip layout;

again, depending on chip's inner architecture, the mainboard may fail to work with 256 MB modules with only four or with 16 chips on it

eight chips may then normally work

- bad / old mainboard BIOS

- another RAM module inside, that blocks resources

try the 256 MB alone, first slot

- badly programmed SPD EEPROM, try to disable auto detection in BIOS setup

...

Don't take the single sided / double sided aspect to serious, as even if both sides of the module are equipped with chips, they may still be electronically arranged as single sided / one bank, and vice versa.

In many cases, though not always, four chips or sixteen chips are double sided / two banks, eight are single then.

Of course, only talking single data rate SDRAM here.

Edited November 20, 2008 by FishBowl

[starcraftmaster]

would a bios update doing any thing?

my bios is old so not sure were i would find one

[sleepydvdr]

That's exactly what I was going to suggest. Go to the website of your motherboard's manufacturer. Just make sure you get the right bios or you may corrupt the system. Also remember that you will lose all your settings in the bios, so you may want to take note of your current settings.

[puntoMX]

but in one slot i got a 256 mb mb stick with is double sided

It is seen as 2 banks, (eg. 0 and 1), I think that is what eyeball wanted to say.

Of course, only talking SDRAM here.

Remeber that we still use SDRAM when we are talking about DDR/DDR2/DDR3/DDR4 .