I had a mac radeon 7000 pci that I converted to pc,but I didn't really gain anything but a card that works in a pc.Most of the computers I had didn't
even recognize the card at all.I had to stick it in an old P3 pc and flash it with a DOS flasher.Finding a bios was fun,since 99% of the info on the net was to convert the card to mac and not vice versa.
The 8pin eeprom holds 128k,which the mac firmware is but the pc firmware is around 50k.I did make a backup so I could go back and forth from pc to mac if needed.It will work with leopard but no kext.