Take the side off the case - leave it running for about 5 or 10 mins - if
the temp drops - it is down to pool ventilation in your case. I had the same
problems when I upgraded my PC to AMD at Xmas.

I took the side off my case - and the temp dropped 20 degrees in 10 mins.
This prompted me to chase my case for one with more ventilation where I
could istall additional fans on the side and on the rear. I also replaced my
processor fan for a "Coolermaster Aero 7 Lite Alloy Extrusion + Aero Fan Amd
Cpu"
eg:
http://www.ebuyer.com/customer/produ...duct_uid=62489

A System Exhaust Blower Fan also helped:
eg:
http://www.ebuyer.com/customer/produ...duct_uid=23879

Hope this helps,

Si.