Where are you reading these temperatures from?
Also, a better HSF than stock will help as even a budget Arctic Cooling Freezer would do a fair job. (There are btter HSF at cost)
Also, is the CPU running at stock speed and volts? What is the default VID for your chip?
If so, perhaps try dropping the voltage/ clockspeed to see if it is that which is causing the problem. When it comes down to it, you may have a CPU with bad IHS contact and if this is causing instability an RMA could well be in order.
I hope my suggestions helps anyway