Well anybody can do that its not required that you put your volts up to overclock as I stated above but at some point you going to hit a point where you CPU wont OC more on stock volts.
For instance I can get one of my CPU's from 3.0Ghz to 3.4Ghz without raising my volts but then to get above 3.4Ghz I have to raise my volts a bit to get more than 3.4Ghz and as I go higher at some points I need to raise my volts again to go any higher.
So you see you need more volts to overclock to the limit in the end.
Neosteve