What is going on???? I can't understand it.

My CPU never got less than 48c idle. Fluctuating 47-50

Overclock [email protected] with abit it7max2 and swiftech mcx4000 with 120mm fan.

I try to run at stock for a day. Indeed, temp are exactly the same as 3.45Ghz ( apply to loaded as well )

What is wrong??

Did you adjust your Vcore? If not, I can see this as an easy possibility. If your Vcore is different between overclocked and stock, then what's happening is weird...

EDIT:
Remembered this is a P4 and thought of something. When overclocked, did you confirm the speed during load? I don't know too much about P4's, but maybe it was speed throttling to keep the temperature down.

yeah

stock speed means stock voltage too

overclocked vcore=1.625V