From my experience with the IN9 its a really decent board for overclocking dual cores, but when it comes to quads its terrible! Thats probably half your problem. For example, my X6800 went to 3.9ghz no probs on this board, but my Q6600 would blue screen at the windows loading screen even at 3ghz. For comparison, 3.4ghz is stable on my EVGA so far, and im still going.

Its certainly not the best board for quads imo.