The system clock determines how fast your PC will operate. This clock is not like a conventional clock that tells the time, but a chip that keeps a beat. This clock acts like the conductor of a symphony orchestra always keeping time. It makes sure that everyone is doing the right thing at the right time.

The clock speed ,or speed of the system clock, is measured in megahertz or MHz. Like miles per hour on a car, the higher the number, the faster the speed. This speed can vary among different models of PCs. It can range from 4.77 MHz of the original IBM PC to over 200 MHz of today's PCs.