I beg to differ. I used a USB 2.0 Card under a G3-powered PowerMac 9500 under OS X and the USB card worked just fine. From what I can tell, USB 2.0 Cards will work in original pentium systems which uses the old PCI slot/specs and they will work in that (like say pentium 100Mhz running Windows 2k Pro with 64MB/128MB RAM). I believed it is mostly driver issues rather than PCI Specs. I have even used the cards in a PowerMac 7500/G3 with a Radeon 7000 PCI and a USB 2.0 Card, and that was what? the first PCI power mac?

Worked fine under OS X, but didn't work under OS 9