I also have a mobo that takes SIMMs and DIMMs. It's the EPoX KP6-LA, based on the i440 LX chipset. It has 4 72 pin EDO SIMM slots, and 3 168 pin EDO/SDRAM DIMM slots. The board itself is slot 1, and will take a PII 233-333 MHz, and a Celeron 266-433 MHz. However, since EDO RAM is so slow, it's almost useless to try to use it with processors this fast.
When I first got this board, I was running my C433 with 128 MB of 60ns EDO RAM (SIMMs). SETI WU's were averaging 25 hours each. I think switched to one 128 MB PC66 CAS2 SDRAM DIMM, and my SETI average WU times drop to 12 hours/WU! :Q