In easy language we can define overclocking as a process in which hardware setting of central processing unit is changed to gain the faster performance of the system.This can be referred as bus speed of mother board.
The chips of CPU are tested by the manufacturer to see at which speed the chips fuse then they set the speed lower then the fuse level.The enthusiastic people set the chips at the fuse level.This whole process is called overclocking.
There are some advantages as well as disadvantages of overclocking.The main purpose of overclocking is to gain speed (about 20%-30%)
Disadvantages
1 The warranty of hardware component will be disabled.
2 Overclocking shorten the life time of hardware component.
3 More power consumption takeplace through overclocking.
4 More power consumption results more heat release.
so the conclusion is that if the system is running well then there is not need to disturb the hardware setting.