I have a 9800 GTX+ and a GTS 250 SLI'd and have no problems, But I did a clean install with W7 Ultimate x64, as I replaced my MB and went back to Intel from AMD. The only problem I seem to have is with the temps. 62*C on the 250 seems a bit high to me. Also do you have the newest driver release? The beta version of 196.34 is what I have installed and like I said earlier am having no problems at all with SLI in W7.