<I have model m35 (386sx and slc version do exist) that has ISA slots, <m25 and m30 can either be 8088, 286 or SX. Model 40 used same board <as m35 except more slots and more drive bays. To differeniate: <starting model series based on MCA from ISA is m50 and up. Ok... by the book: PS2/m25 is a 8086 (xt class) with 3 ISA slots and floppies PS2/M30 is the same with a hard disk. That and the trackstar board was only availabel as ISA that I can find data on. They were most commonly seen around here in Tandy 1000sx/ex machines. the PS1/m25 is 286 as are a slew of other PS1 ISA models but they are somehow modeled as PS1 members of the PS2 family of PC systems. Now we have a subspecies of a species I guess. Bizzare but they are all 85xx-xxx! So much for consistant naming. <BTW, all PS/2, many PS/1s, some Aptivas, any IBM machines were good <made quality-wise even case components and circuit boards. I have a PS2/25 (8530-001) and a PS2/m50z 8550-061 and they are certainly well made and easy to work on. A lot of people like the ps2/m25s as they were ISA and fast for XT with good video and a nice small pizza box. the ugly ones (to some) were the integral monitor varients. Allison