i have my fx 4100 at 4.95 ghz paired with 560 ti and didnt see any need to upgrade to any other cpu. i have my fx set at the borderline of the safe voltage of 1.55 but i have it on a corsair h80 cpu cooler to compensate for the heat. also u gotta set the ram timings to get it to run at higher OC. basically its a trial and error with the ram, voltage and the capacity of your chip and also u goota know wat ur doing.