What Are the Most Important Parts of a Computer?

By John Lister

Modern computers aren't that different from the calculators they evolved from.
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One of the first machines that we would recognize as a computer, the 1940s Collossus, was the size of a small truck and featured more than 2,000 electrical valves. Today's computers can be small enough to carry and are packed with intricately placed wires and tiny parts. Amazingly, though, the basic components of a computer remain the same; each piece ultimately helps the computer perform one of a few basic tasks: storing, accessing, processing and displaying information.


The processor is the part that actually does the "computing." Computers effectively reduce all tasks to a series of calculations, and the processor is the part that physically carries out these calculations. A faster processor usually means a more powerful computer, capable of doing more complex tasks. Many modern machines have multicore processors that are set up as if they were multiple separate processors. The result is that they can carry out calculations for two or more applications simultaneously. This makes the computer far more effective at running intensive tasks such as video editing without slowing down its other activities. Some computers have a separate processor just for handling graphics, which can improve performance.


The most common form of memory in a computer is random access memory. This is a way of holding information for quick access without needing to access a hard drive or other permanent storage. It's a bit like the way the size of your desk determines how many paper documents you can get to quickly without needing to rifle through a filing cabinet. Insufficient memory can slow down a computer's operation even if you have a fast processor. Note than 32-bit operating systems can't give out more than 4 gigabytes of memory, no matter how much you actually have installed.


Storage works like filing cabinets: it gives your computer a lot of room to store files, though it can be slower to access. Most computers use traditional magnetic hard drives for storage, though some use a newer system called a solid state drive, which has no moving parts and can work faster. Some portable devices such as tablets use flash storage, which takes up less physical room and needs less power but is usually only available in smaller capacities. Confusingly this is sometimes called flash memory, but it has nothing to do with RAM.


The motherboard is a relatively low-tech part of a computer but is a very important component. It works a little bit like a spine in a human body. A motherboard is a circuit board that physically holds and connects the various components inside a computer. It transfers information and power between the computers. It also holds a chip that stores a small piece of software called the Basic Input/Output System that controls what the computer does between being turned on and loading the main operating system such as Microsoft Windows.

Media Drives

Most computers have at least one form of drive that can read removable storage. Historically this was floppy drives and later optical disks such as CDs, DVDs and Blu-rays. Today it is most likely to be removable memory cards or sticks that use systems such as flash storage. These can usually be inserted or removed without the need to restart the computer. Some computers do not support memory cards or only take them in particular physical sizes, meaning you may need a physical adapter to read them. Most memory sticks fit a standard USB socket that can be found on virtually all desktop and portable computers, though not all tablets.


Peripherals are anything that plugs into a computer to make it easier or more productive to use. They include keyboards, mice, monitors, modems and printers. Some desktop computers and most portable computers have some or all of these peripherals built into the same physical unit as the main computer components.