Overclocking simply means running your CPU faster than the Stock Speed Intel sets the CPU to run.
In many cases Intel will build a number of CPUs using the same exact process and same exact materials. They will set some at default speeds of Low, Med, and High.
You can choose to by one at the "Low" default speed and simply use the settings in your BIOS to set it to "High".
It would use just as much power and last just as long as if you had overpaid for a "High" chip.