When installing EDO memory, must each pair of RAM sticks be of the same size and brand?

[Wirehead]

I am building my second rig from a bunch of old unknown parts. I had no problems with my first rig as I was manily using new parts. I noticed that when I put the 4 RAM sticks in that sometimes the post will read 8mgs or 16mgs or 24mgs depending on what order I place the same four RAM sticks in the SIMM slots. Also at times depending on the combination of RAM sticks used, during post I get a memory error and the post hangs and tells me to press F1 to continue. I have about 10 sticks of RAM and no two are the same as far as brand. Also if I turn on the memory parity check in the bios some chips will cause an error during Post. Will the rig still run with memory that fails this parity check? Some of this RAM may also be Fast Page and not EDO. Is there an easy way to tell the difference?

 

[Vegito]

They have to be the same size but not same brand. You should have two 4mb at same speed also.. different timing you get weird errors, general protection faults. I don't know how to tell FPM and EDO but was told they're similar.

Try going to the computer show and have them test the memory that you "pretend" to sell and it'll say what the memory are

 

[hubbs]

I think the older SDRAM computers required a low density ram. I do not know however if this applies to EDO ram?

 

[Vincent]

The parity option is to tell your computer's BIOS if your RAM chips support parity error checking or not. I think modules that support parity have 9 (or 18) chips whereas modules that don't support parity have 8 or 16 chips.

I can confirm that the modules don't have to be the same brand but they have to be the same size.

 

[Mday]

well, old SDRAM computers had the intel chipsets (VX?, can't remember) which only supported 64MB of RAM for 2 32MB dimms.

as for SIMMs, for Pentium pcs, they must be installed in pairs, while you can have different pairs, the 2 that make up any pair must be the same size. i don't know about having the pair be EDO and FPM. but you can have a pair of EDO and a pair of FPM.

this fact is due to the bit width of the SIMMs being 32 bit while DIMMs are 64 bit. so you need 2 SIMMs to make up for it in PENTIUM systems.

 

[Wirehead]

Thanks for all the good answers. That is exactly what I was looking for. Thanks again.