DoogUK is right. According to
Micron, these SIMMs only came as 5V units. If there were any 3.3V models made, they were proprietary, and not common (I've never seen one, but I have seen 32-pin SIMMs!).
The Micron pdf linked above should give you enough info to figure out what you've got. I usually look at the individual chips on the board, and go from there. If you see eight xx44256-80 chips on there, then every two chips gives you 256Kx8, four gets 256x16, and you wind up with 256x32 counting all eight. Divide this by four to get 8 bit-wide, which means you multiply by four to get the memory count (32b/4=8, 256Kbx4=1024K). So, that SIMM would be a 1M SIMM.
Most chips are marked similarly, with xx#1#### meaning "by 1 bit", and xx#4#### meaning "by 4 bit". The last numbers indicate the capacity, usually 256, 512, 1024, etc. The number after the hyphen is the speed, in nano seconds, a "-80" or "-8" meaning 80nS.
Hope this helps...
banzai
