It's better to overvolt your CPU when overclocking to more than required because the cpu won't overheat unless it's using those volts so even if you go over the normal or (recommended voltage line it's ok because like I said before those volts won't be used unless the clocks can match them. It is also better to have more than not enough. Of course don't go stupid because remember Intel don't recommend overclocking beyond normal design specs. So overvolt enough just not too much. I'd say for a E7300 VTT 1.4V, NB 1.4V V Core 1.4V. Thankyou and good luck. Don't go frying those boards now. Also remember about the voltages, you'll need the extra voltage for stability or Windows won't respond well.