I installed one onto my Sawtooth G4 and plugged my Maxtor 120gb into the card and tried to boot. About 30 seconds into boot, the Apple logo is replaced by one of those "do not enter" signs, the circle with a diagonal line through it.
I then plug the HD back into the onboard IDE controller and that works fine to boot. Does anyone know if I am b0rking things? Can I use this PCI card to boot from? Anyone?