hi i have an asrock n68 s motherboard with an amd phantom x4 960t black edition cpu and i run windows 7 with b.i.o.s 2.10 my question is how do i safely over clock it i tried asrocks oc tuner and i nudge it up one at a time but before i even get half way my computer freezes i used this oc on a friends board which is the same as mine only diff is his cpu was a amd athlon x4 620 and i could get it up all the way into the red why is this diff with my cpu