So I am overclocking my i5 4670k and i cant get it past 4.2ghz. I have a noctua nh-d14 but the minute I raise the voltage past 1.2 and the clock past 4.2 my prim95 test crashes the pc within seconds. My temps never get higher than 68C and i currently have xmp enabled, do i just have a bad chip or is their anything else i can do?