First, what is the amient temp ?
2) Why motherboard (sensors may be reading wrong)
3) What HSF, and did you use thermal paste ?
That cpu will probably be fine at 65c, 70c tops.
BUT, it should not be running that hot I don;t think, however a lot depends on what the answers to the above questions. My Opterons, one idles at 50c, the other at 46c, but I am not sure I believe my sensors, especially since I have identical HSF units, and the case side is off at the moment. And the same HSF keeps my Athlon64 3000+ stable at 2.2 ghz at 32c idle.