Computer technology has spawned a vocabulary populated with abbreviations, acronyms and outright jargon. Some of these terms only make sense to computer technicians and engineers. Others make a useful contribution to your ability to evaluate and compare computers, understand their specifications and select options with which to customize them. Of these terms, GHz and RAM each abbreviate critical concepts that apply to every computer you encounter. When you measure CPU speed or talk about system memory, these abbreviations take on important meanings.
Hertz, Megahertz, Gigahertz
One hertz consists of one cyclical movement between two states of a device or property. In computers, it defines the clock frequency that measures the timing of the operations your CPU performs. For a computer, one hertz goes by in far less than the blink of an eye. A component whose speed measures one megahertz performs one million operations per second. At the gigahertz level, that speed climbs to one billion operations per second. To simplify the notation of this unit of measure, it abbreviates as GHz.
To find the most-common computer component to carry a speed measured in gigahertz, look to the CPU plugged in to your system's motherboard to serve as the brain of your system. The CPU's operations process at a high rate of speed defined by an internal clock. An external clock times those operations that involve obtaining data from system memory. This second clock runs at the slower speeds at which memory operates. Because memory chips provide access to any of the data they contain without forcing the CPU to process it in a specific order, they carry the name random access memory, or RAM.
Thanks for the Memory
Just as CPUs continue to speed up throughout the evolution of personal computers, so do the RAM chips they use to hold operating-system and software data. Computers today can access and use more RAM than early systems could hold, and the modules that provide that memory offer greater capacity than early RAM modules could contain. These modules gain their total capacity from the aggregate of numerous smaller chips, installed on tiny circuit boards that snap in to sockets on the motherboard.. Whereas early systems offered memory capacities in the megabytes -- millions of bytes -- systems now accept individual RAM chips that can hold gigabytes of data.
Like CPUs, RAM chips also run at specific speeds. Some list their performance in terms of megahertz; others specify how many megabytes of data they can process in a second. The prefixes "mega-" and "giga-" always refer to millions and billions, respectively. Because video cards now incorporate their own processing units and memory, acting almost like separate computers, these components also list processing speeds and amounts of RAM. In fact, you can find video cards with gigahertz speed and gigabytes of RAM.
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