Since you didn't mention BSODs, random reboots and good old fashioned crashes, I would question the acuracy of your temp sensor. If you can hold your finger on the top of the hsf and not feel like its burning, it's the thermal sensor. If that's the case I would rma the board. If the chip is getting that hot, and you are sure you have the hsf on right way round, I would check the voltages to the cpu.
that's just crazy!!! my block heater (T-Bird 1400) doesn't even go that high~~ try using several different programs to check the temp and as long as u can put u finger against the HSF for 10 second without screaming, it's probably broken heat sensor
Proud Owner the Block Heater
120% nVidia Fanboy
I'd get a nVidia GeForce FX 5900Ultra... if i had the money and if THEY WOULD CHANGE THAT #()#@ HSF
Heh and here i am worrying about the summer heat. Its 30C in my room now and my 2.2ghz tbred on 1.8v is idling at 43C. Ok so I cheated slightly and bought a 12" fan and took the side panel off but its either this + 43c or panel on and 51C.... BTW I think this fan shifts 10,000CFM or something LOL. Nice and quiet though