I have yet to see any real issues with 266.58 whql. I liked the 266.35 beta but with the aa bug, I figured I'd give whql a try. There about the same to me, if there is better IQ and performance fixes I don't notice them much. I am mainly playing CoD BO right now. I did not see any real performance increase over the beta but whqls don't compare whql vs beta but whql vs whql and the 266.58 are better than the 260.99 whql.