Ram not recognized

[DKruciak]

I read another thread about "ram not recognized" with interest, because I have that problem too. I am helping someone upgrade the memory on a motherboard (Make unknown) that was built around May 1996. It is a board with a Pentium chip(120) with 4 72 pin Simm slots. Bios is Phoeniz 4.04. Two slots are occupied with simms that have the following handwritten on them: NRM 2.9 AO 2X32X60 EDO. May5, 1996. Each has 16 chips on them, 8 on each side. The computer has 16 megs of memory, so I believe that they are 8 meg simms. I tried to add 2 more 8 meg simms, EDO, but that have only 8 chips on them, but had problems with the BIOS recognizing them. If I leave the first two old ones on, and put the two new ones on in the 2 available slots, the BIOS only recognizes 24 megs of memory, I get a "memory test fail" error message before startup, and a Windows Protection fault and lockup after startup. If I just use all new simms, the BIOS does not recognize them at all. I have tried different combinations of old and new without success. I have read all that I can on memory and memory types, and have upgraded memory many times before without problems. What am I missing here, and how can I avoid this problem in the future? Is there some source of information, (book or web site), that might have helped me on this previously?

[ENVY]

Well,It lookslike they are all edo ram.I would suggest taking the new ram in for a test.It really sounds like one of the new cards has a problem.This is pretty common.Since you can get it to register 24mb and are getting memory errors then It pretty much has to be the ram.Good Luck

[SIMON wALTON]

Hi,

I'm the oe that posted the RAM not recognised. The answer from the Techies for my problem was that on the early optiplex motherboards there was probably a maximum of 8 mb RAM per slot possible.

For some reason when putting 2 * 16 Mb it only recognises 4 Mb per slot. Thus putting in 4 * 16 mb only gave 16 mb. However by putting in 4* 8 mb we were able to get 32 mb of RAM.

Because of the need to get the PC to my son I was not able to look into (not that I know how) the BIOS to see if there was a constraint

Hope this might be of help

cheers

[DKruciak]

My thanks to Envy and Simon Walton for taking time to reply to my inquiry. Here is what has happened since then.
I took the additional SIMM's to a local memory supply company and had them tested. The SIMM's were fine, but tested for a 4K refresh rate. I exchanged for 2K memory refresh rate SIMM's and got mixed results.
In the older Pentium 100 with Award bios v4.50G and a SIS chipset, I put all the new ones in and got 24 megs of memory again, but with no memory test errors, and no GPF's in Windows startup.
In the newer Pentium 120 with Award bios v4.51P and the Intel FX chipset, the four old double-sided SIMM's were put in, and the computer correctly saw the 32 megs of ram.
I went to the Wim Boev's (forgive me if I spelled his name wrong) Bios page to try to find more info on the board and bios, but did not have much luck. The bios code is 2a51apa1, which I think is a EPOX board. But could find no info on their site that might help. Award was bought by Phoenix, and could not info on their sites either.
This may be a dumb question, but I'll ask it anyway. Is there a charge for Bios upgrades? Could the fact that the newer board has a later bios be why the older board does not recognize all the memory? Could it be as simple as a jumper setting somewhere? I looked for one on the board, but could not find one, as well as not finding a name of the manufacturer on the board.
Thanks for taking time to read my ramblings, and if you can think of anything else, I would greatly appreciate it.