Updated: 09/12/2023 by Computer Hope

A component may refer to any of the following:

Heat sink computer component

1. With hardware, a component or part is one hardware unit designed to connect to and function as part of a larger system. For example, an integrated circuit can be considered a motherboard component, and a video card can be considered a computer component.

Components in a computer

Below are the internal components of a computer chassis (case). Clicking any of the links below gives you further information and pictures.

  • CPU (central processing unit).
  • Disc drive: CD-ROM (compact disc read-only memory), CD-RW (compact disc re-writable), DVD (digital versatile disc), or Blu-ray.
  • Expansion card: ISA (Industry Standard Architecture), PCI (peripheral component interconnect), AGP (accelerated graphics port), and PCI-X (Peripheral Component Interconnect Extended).
  • Fan (heat sink).
  • Floppy drive.
  • Hard drive: HDD (hard disk drive) and SSD (solid-state drive).
  • IDE cable (data cable), new computers use SATA (Serial AT Attachment).
  • Motherboard (see page for motherboard components).
  • PSU (power supply unit).
  • RAM (random-access memory).

An external component is often called a peripheral.

Components in a server

Most servers have many of the same components found in a computer. However, servers are designed to run resource-intensive applications and handle the multiple users who log in and run those applications. For those purposes, servers often have multiple CPUs, higher quantities of RAM, and larger storage capacities. The most common components installed on a server are listed below.

  • CPU - 2 or more processors are common.
  • Expansion card - Multiple PCI network cards are common.
  • Fan (heat sink) - Multiple fans dissipate the higher amounts of generated heat.
  • Hard drive - Larger sizes, like 4 TB or 8 TB, or multiple smaller sizes, like 1 TB or 2 TB.
  • IDE or SATA cable - These cables are run throughout the server to connect components.
  • Motherboard - More robust models can accommodate multiple CPUs, higher memory count, and multiple hard drives.
  • PSU (power supply) - Higher power output, like 1000 watts or more, is common.
  • RAM (memory) - 32 GB to 128 GB is common.

What is the most important component of a computer?

No single component in a computer is considered the most important because no component can work alone. Many people immediately say the CPU is the most important component; however, the CPU cannot communicate with other components without the motherboard. Some may argue the motherboard is the most important component because it allows all devices to communicate with each other. However, a motherboard cannot work without a power supply, which supplies all other components with power.


See our computer term page for a full explanation of a computer with the main components that make up a computer.

How many components does a computer have?

This question varies depending on the type of computer and if you want to count the components that make up a component. For example, with a typical desktop computer, you could say the computer has five components:

  • CPU
  • Motherboard
  • Memory
  • Power supply
  • Hard drive

Although this answer assumes that the motherboard has an integrated network card, sound card, and video card. If any of these cards were expansion cards, they'd be considered an additional component. Also, this number does not consider any fans or heat sinks as a component. Finally, if you consider each of the smaller components required to make a component work, like a motherboard (e.g., ICs, capacitors, etc.), a computer has many more components.

2. With software, a component is a segment of code designed to be executed as part of a larger program.

COM, Hardware terms, IPB, Part number, Peripheral, Programming terms