I think some mobo vendors had issues.
My chantech VNF4 Ultra mobo would only post via pci-e v card. But for most part, all agp /pci-e mobos should post with just a pci vcard also ...
Looking to upgrade my 7900GT pos cooler to something nicer... If u got one laying around with all the bolts and stuff.. let me know how much u want for it !
heres is the GTO2 Fron newegg with a quick bios flash to a 850 xt pe and a slight overclock
http://service.futuremark.com/compare?3dm06=132938
6600gt to a x850 xt pe is like night and day !