According to someone from the InsanelyMac forums, it is possible to run Leopard on a 790i ultra motherboard, although it is difficult. I myself have a striker II Extreme, and boy, its giving me HELL! I tried sata AND ide and no success. on the insanelymac forum theres a thread regarding leopard on 790i mobos, it has a jpeg/pdf of the bios settings that might help. I hear Leo4All works the best with these motherboards, but im unsure.