Reported RAM less than actual RAM

[thomsk]

I added a 32MB PC100 SDRAM to my P200 IBM 300GL but the computer reports only an additional 16MB. Removed the original 16MB SDRAM and replaced it with just the new 32MB SDRAM, and the computer still reports only 16MB! Tried the new SDRAM on a newer PC (Celeron) and this motherboard saw the 32MB just fine. A friend told me to try changing the "AGP aperture" option in the BIOS to 32MB but couldn't find this anywhere in the IBM 300GL setup. Has anybody had some trouble like this before? Thanks in advance.

-thomsk

[greggx101]

Had a similar probem yesterday,put a 128 meg dimm in a server and it only reported 7 meg!!
Tried the dimm in another slot and it was fine, the motherboard dimm slot is faulty.

Hope its under warranty.

[greggx101]

p.s do you have a spare slot to try it??

[thomsk]

Thanks for the post, greggx101, appreciate it. A friend says the two existing RAM slots in my system constitutes a memory bank which should contain a PAIR of SDRAMs of "the same size and density." The original SDRAM was 16MB occupying one slot, to which I added 32MB on the remaining slot, which the system therefore reads as two 16MB SDRAMs. Think this figures?

[reboot]

Welcome to the sh***y world of IBM.
Ram MUST be identical in pairs for the MB to recognize it, otherwise it reports only a doubling of the smallest chip on the board.
Jim

[Sterling]

The issue is not one of IBM as reboot pointed
to but to the way the data buses were configured. As your friend pointed out you have 2 "banks" that are comprised of two rows each. The Pentium and Pentium Pro have 64-bit external data buses - 8 rows of 8-bit wide memory to make up one bank. All of the rows that make up the "BANK" must be filled with identical chips (size and speed). That concludes this class on confuser history.
Have fun.

[This message has been edited by Sterling (edited 03-14-99).]

[Dash]

Doesnt the Pair only apply to SIMMS? DIMMs dont have to be installed in pairs, but try pulling out all your simms if you have any, then plugging it in, some Motherboards report DIMMS strangely when Bank 1 of SIMMS is filled.