Can it be done? I don't have any special settings in the BIOS or anything. 72-pin FPM simms in a Socket 3 system.
IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2
Socket 3 = later model 486. If the board does not require PARITY yes you can mix them IF they are same speed and similar density. Ideally you would use all same modules but if you have a 4 slot 72pin board then typically (even if undocumented) they would be Bank0 and Bank1 with two slots each bank. Each bank should have same type modules. One thing you may run into is that some socket 3 treated double sided SIMMS as double slot so you could not use 4 double sided SIMMS as it will skip slot 2 and 4 in memory count and useage.
Curious which board do you have ? Some server/workstation boards required parity even if there is no BIOS setting to set as parity/non-parity.
Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun
This depends on chipset I guess.
On Pentium 2/3's the 440BX chipset is capable to mix ECC and non-ECC, but it is SDRAM.
However, I am not sure whether it operates the bank(s) with the ECC module in ECC mode at all.
