I think you may have too much paste. Thermal paste has an excellent heat transfer, but can't hold any heat. If its too thick, it can't transfer from one surface to the next, instead just transfers it back to the original surface, so to speak.
You could try pusing down while rotating the heatsink to make sure the contact is good, it may also squish the paste out, wich wouldn't be a bad thing.
good call, i removed heat paste from heatsink, then reseated it. My temp went down by 10c.... now it is reading 57.8c under full load....thanks