had it running stable on 3.2 (8x400), reverted back to standard after I had some Evo crashing but think thats more likely a nvidia driver issue looking back. Will probably go again for 3.2 if I find the time to do it on a weekend. I pushed it once to 3.6 was stable as well but had little temp issues as I run on air, so I think 3.6 is about the max you can go for without water cooling and such