I have a PowerMac 7500/100 upgraded with a 400mhz g3 card from sonnet. I also purchased a PCI USB card and a PCI Firewire card. The firewire card works find with my IPOD. USB card works fine with a USB keyboard, mouse, and a Zip drive. However, whenever I try to use a USB external hard drive, I have problems with the system freezing when trying to copy files to the drive. I seem to be able to read files fine, but if I try copying over a few hundred files, it will eventually give me the spinning wheel, the hard drive light stays on, and the system freezes. I also tried an external firewire drive and had the same problem. Both cards had mac compatible logos on the box. Any ideas? I have tried going back to the ADB keyboard and mouse and unplugging all other devices to make sure there were no conflicts. Same result. Any help appreciated.