What the - ?

[daveymark]

My mobo only supports PC100 RAM (512mb per dimm slot). I know I can use PC133 - backwards compatible.

I have PC133 256mb chip - when I put it in (even alone with no other ram), the computer only sees it as 128mb. Tested it on my friends computer (3 different computers) - it registers as 256. What gives here? Can someone help me?



Specs:
Motherboard Properties
Motherboard ID 10/15/2001-i440BX-
Motherboard Name
Asus P3B-F

Front Side Bus Properties
Bus Type Intel GTL+
Bus Width 64-bit
Real Clock 114 MHz
Effective Clock 114 MHz
Bandwidth 912 MB/s

Memory Bus Properties
Bus Type SDR SDRAM
Bus Width 64-bit
Real Clock 114 MHz
Effective Clock 114 MHz
Bandwidth 912 MB/s

Motherboard Physical Info
CPU Sockets/Slots 1
RAM Slots 4 DIMM
Form Factor ATX
Motherboard Size 190 mm x 300 mm
Motherboard Chipset i440BX
Extra Features JumperFree

Motherboard Manufacturer
Company Name ASUSTeK Computer Inc.

[Etruscan]

In a nut shell - the RAM is backward compatible, (that is it will work at 100mhz), however, the mainboard is not upward compatible (it will only take PC100, it cannot support PC133).

[daveymark]

Oh, so it has nothing to do with the number of CAS lines on the DIMM, then. (Some are 'double sided', which means they have twice as many CAS lines as 'single sided'. )

Besides, my mobo is 133 compatable. If it wasn't, I would see -zero-, not 128M.

whew.

[Atomic Rooster]

You may be on to something there davey. Maybe your mobo doesn't support dual density RAM.

[daveymark]

thanks for pointing that out! Those wacky folks at ezbpc don't know what they're talking about...

[Eladijaz]

Greetings,
That's correct, it's all to do with the way the memory chips have been arranged on your RAM ... you need to get hold of some that has 16 chips on the DIMM (and even some of these won't work). Unfortunately, alot of 256mb DIMMs won't work on BX chipsets.
Regards,
Elad.