Abbreviation for
gigahertz. One GHz represents 1 billion cycles per second. The speed of
microprocessors, called the
clock speed, often is measured in gigahertz. For example, a microprocessor that
runs at 200 GHz
executes 200 billion cycles per second. Each
computer instruction requires a fixed number of cycles, so the clock speed determines how many instructions per second the microprocessor can execute. To a large degree, this controls how powerful the microprocessor is.