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# What is MHz?

Article Details
• Originally Written By: Sherry Holetzky
• Revised By: G. Wiesen
• Edited By: Bronwyn Harris
2003-2019
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MHz is the abbreviation for the word "megahertz," which is a unit of measurement for frequency in science. One cycle per second is measured as one hertz (Hz), and 1 MHz is equal to 1 million Hz. Frequency is important in measuring a wide range of electromagnetic signals and waves, including available bands for radio broadcasts and clock speeds in computers.

#### Basic Meaning and Functionality

Hertz can be used in the singular or the plural. It is the common unit of measurement for frequency, counting the number of cycles completed in one second. In fact, before the implementation of the term "hertz," the measurement was actually called “cycles per second” (cps) and MHz were called "megacycles." One MHz denotes one million hertz or one million cycles per second, and also equals 1,000 kilohertz (KHz). These different unit sizes are used in various fields, such as radio broadcasting and computer science.

Scientists measure sound, light, radio wave frequency, and electromagnetic radiation in hertz. Sound generally ranges up to tens of thousands of hertz, while scientists often measure physical vibrations in MHz. Radio frequencies generally include a wide range of values, from about 3 KHz to 300 GHz. Different types of light and rays, such as gamma rays, are measured in even higher ranges and are often described by other terms such as "wavelength."

#### Computer Processor Speeds

MHz is commonly used to describe the measurement of speed for a Central Processing Unit (CPU) in a computer. Each function of a computer involves instructions that must be processed by the CPU. The CPU sends those instructions at a certain number of cycles per second, called the clock speed. Higher speeds indicate more cycles per second, which in turn means that the computer can perform more operations or run faster.

Computer companies also use MHz to measure the clock speed for other components such as video cards. Using software on a computer that is graphics intensive, such as playing games, editing video, or rendering artwork, can place tremendous demand on the CPU. Graphics cards have a Graphics Processing Unit (GPU) that handles these operations, allowing the computer to utilize both chips for such programs. Since higher MHz means better speed and performance, having a powerful CPU and graphics card increases how well such software runs on a system.

#### Origin and History

The term "hertz" is named for Heinrich Rudolf Hertz, who contributed significantly to the study of electromagnetism. Abbreviations for units within the International System of Units are capitalized if named after a person, but are not capitalized when spelled out fully. That is why the abbreviation is "Hz," but the term is written out as "hertz."