I exchange my Core 2 DUo e4600 for a Core 2 Quad q6600 and on Speed Fan software i noticed that on pcsx2 emulator my CPU reach to 80ºC of temps... On the rest the temps are fine...
If you are using the box HSF then could be, those LGA775 quad cores are really hot when at full load. Best thing, if the case, is to go for an aftermarket cooler, like the CM 212+ or the EVO.
A friend told me too that is normal... I already opened the case and the CPU fan is not hot indeed! But we never know! Right know he is at 50ºC (im just on the web,nothing more) ...
You are probably with the stock HSF. Redoing the thermal paste with a good branded one (e.g. Arctic Silver) could help. Otherwise, an aftermarket one could settle temps down a tad more.
Don't... This one was bought on eBay... The CPU too and didn't came with a cooler.
I have to say that before apply thermal compound,when i was removing the heatsink to do it,i didn't notice that one of the 4 pins was a bit stuck yet,so it broke when i forced to got out the heatsink... but i were succeed in fix that pin with universal glue... I dont know if that have something to do with! Cause the Fan is well fixed to the CPU/Board! :/