My understanding of PDS slots is that they are all electronically compatible with each other, but not necessarily physically compatible. I have a network card that I got with an LC II that I have put in an LC III (68020 processors in both machines), and now it's installed in a Performa 580 CD (68LC040 processor.) I wanted to put it in my Mac II FX, but it wouldn't physically fit (the jack on the back of the card wouldn't line up with the slots on the back, but the FX does have PDS slots.)