I have run SLI in all 3 slots with no problems! I have 2 9800gx2's in quad sli and at first I had one in the top blue slot and one in the bottom white slot. I later put the second card in the second blue slot and it also worked just fine. What I am trying to figure out is why with TURBO on and HT on, my cpu will instantly back down to 4ghz from 4.2 ghz when I start prime95. With HT off this does not happen and the temps look fine. Is it related to the voltage? Does anyone else have this problem, as this is the only problem I am having....