try speedfan or another program to see if the mb thermal sensor is fine. if the temps still reading hot. check that you have all the cpu legs in where they clicked.make sure you used thermal paste on the kit and removed the plastic cover from the heat sink.
The stock cooler came with a pre applied thermal paste which in some benchmarks scored better than arctic silver...so that is good stuff....all legs clicked into the mobo and sit properly....interestingly, there is very little noise...which sort of indicates that there is not much load on the fans i guess??