I have been getting some awfully high temp readings in AIDA64, HWMonitor, and Core temp, 100C at the most while running Prime 95 blend test. Even though I am using a Hyper 212 EVO cooler and the chip is still at stock speeds. I have already reseated it once and I am using artic mx 4 TIM. I have installed 212+'s and 212 EVO's many times. I have a costa rican 3770k in the same room with a EVO on it that never got over 80C running prime overclocked at 4.5ghz and 1.25 vt.
More likely, poor contact. remove cooler, clean thermal paste with rubbing alcohol and qtip, reapply thermal paste (try not to use stock garbage and get something decent if overclocking like that, like Arctic Mx-4 or my fav Tuniq Tx-4) using a BB sized dot only! don't even spread out, just place heatsink down flat, do not lay on at an angle, tighten screws evenly a little at a time as you go back and forth on them. then try again