If you bought a box packed processor, you should have got a heatsink fan combo along with it. This heatsink has a thermal pad on it. If you didn't remove the tape covering this pad, thats your problem. If you didn't get any heatsink fan combo, you bought an OEM cpu. In this case, I would recommend taking off your heatsink, removing the thermal grease and get an AMD recommended Thermal Pad (its different from thermal grease). This should take care of your problem