if you are already getting above 30 FPS with one high end video then why would you need 2 video cards?? With a 6800 ultra or an X800 you get great frame rates with highest settings and 4x aa and 8x af... sometimes even about 80fps on some games with all those things up... People actually forget that the average FPS to be running smoothly is 30... so if you are getting 60 - 80 FPS and even higher then why would you need SLI??? Its just for rich people who want to have the best technology when they snap their fingers and want all the bragging rights! Doom 3 is a very demanding game and with an x800xt you can get 40 - 50 fps with ultra graphics and 4xAA and 8xAF... YOU DONT NEED HIGHER THEN HIGH FRAME RATES AND DONT WASTE MONEY ON SLI!!!