Memory has different value in two PCs?

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

Hi,

I just bought a 2nd hand 512M 133 SDRAM. When I put it (on its own) in an
Athlon 800 PC it says it is a 256M chip but when I put it in an old K6/2 500
PC it reports it as 511M.

Anyone got any idea why this is?

Regards,

John Smith.

Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)

"John Smith" <J.W.T.Smith@ukc.ac.uk> wrote in message
news:c6aqee$c16$1@athena.ukc.ac.uk...
> Hi,
>
> I just bought a 2nd hand 512M 133 SDRAM. When I put it (on its own) in an
> Athlon 800 PC it says it is a 256M chip but when I put it in an old K6/2
500
> PC it reports it as 511M.
>
> Anyone got any idea why this is?
>
> Regards,
>
> John Smith.

Wow, ironically, the socket 7 board is more advanced. Likely, it is a
16-chip DIMM (2-sides), so it would be a 256x16 DIMM. So, each chip is
256Megabits. For some reason, the Athlon board doesn't accept 256Mbit
chips, but will accept 128Mbit chips (1/2 of the 256Mbit; so it reads 256MB
of the 512MB DIMM). So, each chip is only being used 50% in the Athlon.
There is nothing wrong with the DIMM.

If it is single-sided, though, then it makes things a wee bit weirder.
Because then it would be using a 512x8 (eight 512Mbit chips). It's a
stranger configuration, since 512Mbit chips are more expensive. Even
stranger, is that a Socket 7 motherboard is able to use a 512Mbit chip. I
don't believe I've seen any that do. It would certainly be possible, just
rare. Likely, though, it is double-sided.

By double-sided, I mean 16 chips, and single-sided means 8 chips (or
less..but a 1024x4 isn't likely at all).