Using a PC PCI ATI VGA on the Mac

hi, has anyone tried to use a PCI ATI 128 card or any other PC PCI vga on their Mac. The BIOS is probably gonna be incompatible, but since Linux uses a framebuffer it should be ok after initial boot. Is this true ? cheers btw I'm looking for a ATI card in the UK to upgrade my 7500 and the Mac versions are really expensive. -- John