Also known as a processor or microprocessor the CPU was first developed by Intel in 1974 and is short for Central Processing Unit. The computer CPU is responsible for handling all instructions and calculation it receives from other hardware components in the computer and software programs running on the computer. Below is a graphic example of what the original Intel Pentium processor looks like.

The central processing unit (CPU) or the processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. It is the unit that reads and executes program instructions. The data in the instruction tells the processor what to do. The instructions are very basic things like reading data from memory or sending data to the user display, but they are processed so rapidly that we experience the results as the smooth operation of a program. This term has been in use in the computer industry at least since the early 1960s. The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same.

Figure: Die of an Intel 80486DX2 microprocessor (actual size: 12×6.75 mm) in its packaging.

Today there are several different manufactures of computer processors. However, Intel and AMD are the leaders in the PC market.

CPU Components

A lot of components go into building a modern computer processor and just what goes in changes with every generation as engineers and scientists find new, more efficient ways to do old tasks.

• Execution Core(s)

• Data Bus

• Address Bus

• Math Co-processor

• Instruction sets / Microcode

• Multimedia extensions

• Registers

• Flags

• Pipelining

• Memory Controller

• Cache Memory (L1, L2 and L3)