What Does Gigahertz Mean?

Gigahertz (GHz) is a frequency unit that measures the number of cycles per second. Hertz (Hz) refers to the number of cycles per second with periodic 1-second intervals. One megahertz (MHz) equals 1,000,000 Hz. One gigahertz is equal to 1,000 megahertz (MHz) or 1,000,000,000 Hz.


Gigahertz is often used to measure central processing unit (CPU) clock speed. In general, higher CPU clock speeds indicate faster computers. That being said, speed-impacting factors include pipeline depth, instruction sets, internal cache, network/bus speed, disk performance and software design.

Techopedia Explains Gigahertz

One gigahertz equals 1,000,000,000 Hz or 1,000 MHz and has a frequency measurement with periodic 1-second cycles. A nanosecond is one-billionth of a second or one-thousandth of a microsecond. A nanosecond’s numeric order is 10 or 0.000000001. Hertz is based on total rotations per second, that is, one full second rotation equals 1 Hz. One kilohertz represents 1,000 rotations per second. One megahertz represents 1 million rotations per second. One gigahertz represents 1 billion cycles per second.

Clock speed, which is also measured in hertz, refers to synchronous circuit clock frequency, for example, a CPU. One clock cycle lasts only 1 nanosecond and toggles between 0 and 1. Modern and non-embedded CPUs may have a single clock cycle of less than 1 nanosecond. CPU megahertz usually refers to clock rate, frequency or speed. Clock rate is gauged by a crystal oscillator which generates highly accurate and unwavering electrical and clock signals, stabilizes receivers and frequencies, and tracks time. The oscillator circuit brings its crystal a small amount of electricity every nanosecond, which is measured in hertz.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.