Types Of Computer Hardware – Processing Devices

CPU_Processing device

Processing devices are parts of the computer that are responsible for processing or converting data into meaningful information. There are many processing devices and the most common ones in a computer include the Central Processing Unit (CPU) and the Graphics Processing Unit (GPU).

The Central Processing Unit (CPU) is the main processing device in the computer.

The Central Processing Unit (CPU)


The CPU is a computer chip located on the motherboard inside the system unit. It is the main electronic circuitry in the computer that carries out the instructions contained in a computer program by performing arithmetic, logical, control and input/output operations.

In other words, the CPU is responsible for performing the calculations and comparisons needed to convert data into information and as well control the computer’s operations. As a result, the CPU is often referred to as the ‘brain’ of the computer. It is the most important processing device of a computer without which a computer cannot perform any of the operations for which it is intended.

CPU_microchipsMost modern CPUs are contained on a single Integrated Circuit (IC) chip and as such are called microprocessors. Nonetheless, the CPU is traditionally referred to as a Processor. A processor can have two or more CPUs or independent processing units called “cores” on a single chip and such is called a multi-core processor. The single processor can run multiple instructions on separate cores at the same time, increasing overall speed for programs to be executed. The microprocessors currently used in almost all personal computers today are multi-core.

The principal components of a CPU include the arithmetic-logic unit (ALU) that performs arithmetic and logic operations, and a control unit that orchestrates the fetching and execution of instructions by directing the coordinated operations of the ALU, registers and other components. Also, an IC that contains a CPU may also contain memory. The CPU register is a small amount of data storage that facilitates some CPU operations. Another storage location is the CPU cache that is a high speed volatile memory which is bigger in size and helps the processor to reduce the memory operations.

READ ALSO : Types Of Computer Hardware – Storage Devices and Media

What Are The Three Working Steps Of The CPU?


Almost all CPUs follow the Fetch, Decode and Execute steps in their operation, which are collectively known as the instruction cycle.

  • The first step, fetch, involves retrieving an instruction from program memory. The instruction that the CPU fetches from memory determines what the CPU will do.
  • In the decode step, the control unit breaks down or decode the instructions in a way defined by the CPU’s instruction set architecture (ISA).
  • After the fetch and decode steps, the execute step is performed. Depending on the CPU architecture, this may consist of a single action or a sequence of actions.

During each action, various parts of the CPU are electrically connected so they can perform all or part of the desired operation and then the action is completed. Although the process is complex, the computer can accomplish it at an incredible speed, in millions of instructions per second (MIPS). The performance or processing speed of a CPU is measured in MIPS with Megahertz (MHz) as the unit of measurement.


The Graphics Processing Unit (GPU)

Graphics Processing Unit

A graphics processing unit (GPU) is a specialized electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images intended for output to a display device. Technically, the graphics card or video card contains one or more GPUs.

The difference between a GPU and a graphics card is similar to the difference between a CPU and a motherboard.


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