If your computer is that fast, I would think that overclocking isn't necessary... Of course, that all depends on the user.
Overclocking changes either the bus speed or the ratio that the CPU is set to. Typically, to overclock a computer, if you have an unlocked BIOS, you can go into BIOS and change the settings... This ends up in increased CPU temperature and (Depending on how much you overclock) decreased stability. To keep the overheating and instability to a minimum, you should get a better cooling system...