I've recently oveclocked my i5-2500K to 4.5GHz (1.3volts, was stable at 1.28, but I'm unsure of what difference that actually makes) and my CPU is always overclocked to 4.5, is this okay, or should it be dropping down when idle?
C1E caused instability; as soon as I ran Prime95 my computer locked up. So I turned it back off.
And isn't it true that as soon as you do the smallest task, such as minimizing a window the cpu jumps back up to OC speed anyways?
Most auto-clock type settings in your BIOS should be disabled when overclocking. Aside from power conservation (something most rig-builders don't give a toss about) having your CPU always at it's top clock isn't an issue unless you have poor cooling (which you obviously don't if you're rocking 4.5GHz).
I'm not sure what would push your CPU back to OC speeds when C1E or something like it is turned on, but most tasks like opening applications would do it.
I prefer having my chip at 4.0GHz constantly without any clock-drops etc.