PC cards will not work in a Mac, Bummer for us. I think SIIG and Sonnet both use acard chips. You can just buy an "acard" based card from acard.com They all seem to work well though. Remember that ATA/133 is a bit of a dream, it's rare to max out a ATA/100 bus, much less a ATA/133. Also, PCI is limited to 133MBps, so if you have any other PCI cards, that will slow things down.