Gigahertz: Billions of cycles per second


Gigahertz abbreviated GHz, is a unit of frequency. One hertz (Hz) means one cycle per second and 1,000 hertz equals one kilohertz, and 1,000 kilohertz (or a million hertz equals one Mhz) and 1,000 MHz equals 1Ghz (or billion hertz). Hz is named after the German physicist Heinrich Hertz who made considerable contributions to electromagnetism.

In computers, the CPU (central processing unit) and other components such as RAM and the video card speed is measured in Hz or MHz (Megahertz) and now GHz (Gigahertz).

One GHz equals 1,000,000,000 (one billion) Hz. Hopefully the table below will make it easier to understand.

Hertz1 Hz0.001 kHz0.000001 MHz
Kilohertz1,000 Hz1 kHz     0.001 MHz
Megahertz1,000,000 Hz1,000 kHz1 MHz
Gigahertz1,000,000,000 Hz1,000,000 kHz 1,000 MHz

For a CPU the GHz refers to the clock speed of the processor. This means that a number of bits (either 8, 16, 32, or 64) are manipulated at one billion cycles per second. Sound fast?

Well that was a 1GHz CPU, (considerably slow now a days, because most computers would have a CPU over 2Ghz which means those bits are now being manipulated at 2,000,000,000 (two billion) cycles per second.

Common examples of GHz are: A Pentium IV CPU (1.6 GHz), running at 1,600,000,000 Hz. Or a 512MB RAM stick running at 233,000,000 Hz.

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