try using this...
http://www.majorgeeks.com/download.php?det=337
to get a "second opinion" about your temps...your bios could be getting a bad reading.
If that still shows up as running hot, then take the side of your case off and see if that makes a difference. If so, you may have inproper ventilation, even though you have 5 case fans, they may be creating hot pockets of air inside the case.
What type of thermal grease did you use?