While many people hail the CPU as the most important PC component, many more would argue it’s the graphics card that is most significant.

After all, you probably won’t notice the difference between a 2GHz and a 3GHz CPU, but the benefits of a high-end graphics card over a mid-range alternative can be more substantial – particularly for gamers.

It’s not just games that require strong graphics performance. The next incarnation of Windows, known as Vista, looks set to require fairly powerful graphics acceleration for its optional 3D interface.

Even ordinary tasks, such as image and video editing, will place significant demands on your graphics hardware.

The good news is that the graphics card market is saturated with products. The two main players, ATI and Nvidia, offer cards to suit every budget, including motherboard-integrated solutions and discrete cards costing anywhere between £40 and £500.

Unfortunately, the sheer range of cards means that choosing one can be something of a minefield.

To help clear up some of the confusion, we’ve carried out an in-depth investigation into the graphics card market to help you decide which technology and products are right for your particular needs.

In PCW’s Labs we perform benchmark testing on the latest graphics cards as they are launched.

We’re continually testing cards from all the major suppliers and add their performance results every week, giving you with an easy reference guide to how they compare.

The attached pdf tables and performance graphs were compiled prior to the release of ATI's new X1900 range of cards, but are a good guide if you are not after a top of the range card.

Otherwise, see the Test Bed's performance results area, which has performance results for over 80 cards.

Over the next few pages you’ll discover the science behind graphics cards, what factors affect their performance, and whether two cards really are better than one.

We’ll even show you how to get the most out of your current card without spending a penny and explain why some cards are better than others for playing particular games.