Did you change the vcore in BIOS or is it set to auto? I bet it is at auto, and if so it upped the voltage by about 6 steps, hence the large jump in temps.
I didnt have to up the vcore until I hit 4Ghz on my stock 3.3ghz chip to get it to stay stable… until I bumped the voltage to get past 4ghz, the temps only increased about 4-5C. once I bumped the volts it jumped up about 10c over stock.