ram problem

[integerspin]

I just purchased a 1 gb stick of the finest, nah not realy it's value ram, DDR400 and have a prob, it's reported as 512mb.
I have 256 mb ddr333 in slots one and two. I wacked the 1 gb dimm in slot three. It booted
OK and flashed through the memtest without me spotting what it said, I checked the ram in wondows and it came up as 1gb[total]..
I rebooted and checked and it came up as 1 gb in memetest so I checked the bios and I reset the fsb and dimm timing to 133 and spd, I haven't tried manual settings yet[which I should try as the board would have been for PC2100-2700].
Reboted still showing 1gb so I pulled the two 256 Mb dimms out and put the 1GB dimm in slot one, booted and it's now reporting total 512MB[sounding like a 512mb dimm]..
I don't have another board here that takes DDR so I can't test in anything else..
What reasons are there for a 1gb stick being reported as 512mb. I haven't stressed it but have had windows running for 8 hours and it seem OK with the '1gb' in it..
I bought the ram in a lead up to an update, I figured I could buy ram and hdd prior to getting cpu, board and graphics card, spread the cost but not have unused kit sitting around..Got a feeling I will be buying the bit's sooner than anticipated..

system.
xp2000
soyo KT333 dragon, 4 years old supports 3 gb or ram.
nvidia mx2 graphics
2 off 256mb crucial DDR333
pair of 80gb ibm ide drives
scsi cd's and a couple of cheeta's[helicopters more like]

[killie99]

Not all 1Gb sticks are the same and not all motherboards support both types. I suspect your motherboard only supports single sided DIMM and the 1Gb stick you have is a double sided DIMM. Post the part number or the part number of the actual ram chips.

[teachmech]

Most new 1GB dimms are now high density and it sounds like your motherboard new low density chips.

[scrandman]

It could also be a chipset limitation. Try removing one of the other sticks and running with the 1Gb & 1 256Mb. See if that makes any difference to how it is recognised.

[integerspin]

Tried all permuations I can..
seems double sided dimms don't work.. all the stuff I can foind onthe boards doesn't mention double sided........

So looks like I am going to have to accelerate the upgrade;-)

[scrandman]

More than likely it's a limitation on the number of banks on any given stick as opposed to it being double sided.