Good news!!! yesterday I installed a Gtx 8800 768mb in my mac pro 3.1!! Im running windows vista 64 bits. 6 gigas of ram 2 quad xeon. I did this because a im running FSX and now with this card and this machine I have 40 fps ultra high in mayor cities!! pc nvidia cards an ati cards work perfectly well in mac pro, running windows vista 64 bits or 32 bits!!! dont worry about the rom, they WORK!