Page last updated at 09:09 GMT, Wednesday, 25 February 2009

Beginner's Guide: Anatomy of a computer

The inside of a computer can look rather daunting, but it is actually quite simple.

A motherboard holds most of the component parts together - either soldered to the board or slotted in - with the hard drives holding your data and the video card turning the electronic information into something that can be displayed on your monitor.

Most of the items can be easily upgraded. Here are some of the easiest items to upgrade.


Power Supply Unit (PSU)

Probably the most underappreciated object inside the computer, the job of the PSU is to supply power to the entire system.

PSUs are rated, in the main, by how much power they can put out: 300 watts, 400 watts etc.

An underpowered computer will fail without warning and even a system with a reasonable PSU can suddenly find itself going wrong if a number of USB devices are plugged in.

However, bigger is not always better, as some of the more powerful fans can be noisier and produce more heat. Shopping round for one that matches your power consumption (and is quiet too) is worth the effort.

Central Processing Unit (CPU)

This is the nerve centre for pretty much every operation the computer executes, processing data and performing most of the calculations. It also controls all the other components in the PC and manages the data going to and from the various components of the machine.

In the past, a rough rule of thumb was that the faster a CPU was in terms of clock speed (in megahertz or gigahertz) the better it was. That might have been true in 1995 but it is not the case today.

These days a benchmark test - a suite of computer programs designed to stress load a CPU - is the best way of evaluating CPU performance.

Most CPU "plug in" to the motherboard with a cooling fan on top. Changing the CPU is easy enough, although getting the fan to fit snugly can be tricky. Remember that a new CPU might make demands on your PSU that may entail an upgrade.

Video Card

The video card performs two functions. It acts as the main interface between your display monitor and the computer and also - via its VideoRam (vRAM) speeds up the rendering of 3D images and textures, especially in video games. Video cards also have dedicated Graphical Processing Units which handle many of the complex calculations related to imaging and graphics.

Changing your card is a simple slot out / slot in affair, with more modern cards requiring their own power source.

Upgrading your video card will give you increased frame rates, allow you to view in higher resolutions and can speed up Windows.

Hard Drive

This is where almost every bit of data is stored for long term use.

The principle of a hard drive has not changed in almost 20 years, with data being stored on a number of metallic disks.

Hard drive guide

You can upgrade your disk to make it faster or larger. In some cases both.

Drives can be faster with faster spin times, although they are frequently noisier. Larger drives can be quieter, but will also be slower in terms of data throughput.

Random Access Memory (RAM)

Ram - or the memory as its commonly known - is where data is temporarily stored by the computer. It is "temporary" as it is all lost when the computer is powered down, which is why everyone goes on about "saving your work as you go along".

The memory sticks slot into one of four slots on the motherboard.

Ram comes in varying sizes with speed determined by its latency timing. Some machines can now address many gigabytes of ram.

Upgrading your ram consists of two simple catches, with the ram slotting in at an angle into your mother board. This can vary from computer to computer, however.

Case Fan

All this electrical equipment generates heat. And heat inside a PC is generally a bad thing as hotter components are more likely to fail or go wrong.

So you need to get the heat out of the case, and the simplest way is to blast it out with a fan.

The trouble is, the reference fans fitted to most computers are rather noisy. There are replacement fans that run almost silently that can remove the same quantity of air from inside your PC but without the accompanying drone.

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