What is clock speed?

To understand clock speed, you must first understand the question, what a system clock?

 The processor relies on a small quartz crystal circuit, called the system clock, to control the timing 

of all computer operations. Just as your heart beats at a regular rate to keep your body functioning, 

the system clock generates regular electronic pulses, or ticks, that set the operating pace of 

components of the system unit. 

Each tick equates to a clock cycle. Processors today typically are super-scalar, which means they can 

execute more than one instruction per clock cycle. The pace of the system clock, called the clock 

speed, is measured by the number of ticks per second. The faster the clock speed, the more 

instructions the processor can execute per second. The speed of the system clock is just one factor 

that influences a computer’s performance. Current personal computer processors have clock speeds 

in the gigahertz range. Giga is a prefix that stands for billion, and a hertz is one cycle per second. 

Thus, one gigahertz (GHz) equals one billion ticks of the system clock per second. 

A computer that operates at 3 GHz has 3 billion (giga) clock cycles in one second (hertz).