Need some help overclocking my i5 2500k

[timk617]

Hi, I'm trying to overclock my i5 2500k, I have an ASrock P67 Extreme4 mobo.
How do I set the vcore manually?
Currently, it's overclocked to 3.8GHz. With 5 runs on Intel Burn Test at very high, the max temperatures reach just under 70C, and the vcore voltage goes up to 1.29.
But from what I've read, it could be overclocked to 4.5GHz at that voltage, but when I set the multiplier to 45, it went up to 1.38, and temps over 70C.
My idle temps are about 33C on each core. Not sure about ambient temperature, but since AC is set to 76F, and its noticeably hotter in my room, I'm guessing my ambient temp is atleast 80F, which is about 27C.
Is that too high at idle for having the coolermaster hyper 212 plus?

 

[timk617]

UPDATE
doing Intel Burnt Test at night, the temps reach like 65C at 3.8GHz, but the vcore voltage actually goes up to 1.30, 1.32 at one point.
Also, I'm having a sort of an issue where when I start up my computer, the fans start running, shuts back off, then completely boots up. Other than that it's running fine.
So, how do I manually set vcore so it doesn't go up so high, or is my chip just not that good?