CPU

Central processing unit (CPU), microprocessor, clock speed: for example, megahertz (MHz), gigahertz (GHz), terahertz (THz)
Refer to your Inside A Computer and Hardware Basics word documents

This piece of hardware (which is found on the motherboard) is effectively the computer's brain. It processes informaion, performs arithmatice calculations and makes basic decisions by comparing information values. When the computer first starts up, this hardware is what receives the first instructions from the BIOS (built-in software in the PS with the first code that needs to be run by the computer when it is powered on - its primarily used to load and start the operating system).
 * Microprocessor (also known as the CPU and processor)**

The main aspects when it comes to choosing a microprocessor is the **compatability** and the **performance**.
 * Compatability** - Not all software is compatiable with every microprocessor as software that's written for one usually won't work with another
 * Performance** - Some processors are much faster when it comes to handling information in comparison to others. This speed and overall performance is determined by many things including the speed of the microprocessor's internal **clock** (below) and it's word size (the number of bits a CPU can process at one time), measured in **bits**. Nowadays, most microprocessors are either 32-bit or 64-bit.

This is the timing device that produces electrical pulses to syncronise computer's opperations and preserves the computer's time and BIOS settings when the computer is turned off. The speed of this is measured in either megahertz (MHz), gigahertz (GHz) or terahertz (THz) for billions of clock cycles per second.
 * Clock**

By Nikki Blower Last Updated: 13/10/2011