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Megahertz (MHz) is a unit of frequency that represents one million cycles per second and is used to measure the speed at which a computer component can perform an action. The frequency of these "cycles" acts as a heartbeat for the component, with higher speeds allowing for more instructions or data transfers to be processed in a given time.

How megahertz works

The clock signal: Electronic components in a computer, such as the CPU, are synchronized by a master clock signal, which is a steady electrical pulse.

A "cycle": Each pulse of the clock is a "cycle." During each cycle, the processor can execute one or more instructions.

Higher frequency = More speed: The higher the clock frequency, the more cycles per second, which historically meant better performance. A 100 MHz processor, for example, can execute 100 million cycles every second.

The shift from MHz to GHz: As computing technology advanced, processor speeds quickly moved beyond the megahertz range and into gigahertz (GHz), or one billion cycles per second. For this reason, you will see specifications for modern CPUs and GPUs listed in GHz rather than MHz.