If you're looking to buy a graphics card, what is it you're wanting it for? Gaming? Video editing? Just a bit of word processing? Have a think about that while we take a quick look at your options.

And they boil down, effectively, to two companies. Of late, if you want to buy a graphics card for your PC, then it's more than likely got the handiwork of Nvidia or ATI behind it. Interestingly, neither of them makes big money out of selling the boards themselves.

How to find the best graphics cards and graphics adapters

Instead they license their technology to third party manufacturers. So, instead of buying a board direct from Nvidia or ATI, chances are you'll be getting one from the likes of Sapphire, Creative, Asus and suchlike. There are literally dozens of makes to choose from, often with little discernable difference between the products that they sell.

But what is it exactly that they will they be selling you? Box specifications tend to be quite daunting, but actually they're not as complex as they look. Here's a quick look at what's what.

First there's the interface type. Quite simply, this is the slot required in your PC to run the card. Virtually every modern day card requires an AGP slot, and virtually every modern day computer has one. However, you'll probably see the box specs say something like AGP 8X, AGP 4X or AGP 2X. The number relates to the throughput of data it can handle.

2X, for instance, equates to 533MBps (megabytes per second), while 4X is 1.07GBps (gigabytes per second). However, once you head up towards an 8X board, you should note that your motherboard needs to support that speed of throughput as well, or else the graphics card's potential is restricted to what the motherboard can handle. It's not that it won't work, it just won't work as well as it could.

Expect to see PCI Express slots slowly grow to become the predominant requirement over the coming years, as AGP's hold becomes eroded. PCI Express will work a lot faster than AGP and is slowly heading to market.

There's a small number of boards that work with an old PCI slot. This is strictly for bog standard performance, though. A PCI interface can't process data at the speeds required for games of even a few years ago, yet alone today's. However, if you're upgrading an old machine that doesn't have AGP support, then a PCI-based graphics card will serve for a workstation machine.

Now, to memory. As you'd expect, the more on-board memory a graphics card has, the more powerful it tends to be. Furthermore, if you're looking to run the very latest games, then the board will be doing a lot of processing, and so will be particularly demanding. Currently, the bare minimum you should look at for serious 3D gaming is 128MB, but expect that to increase as games become more complex. Try to get a board with DDR memory as this should be faster.

Next up, clock speed. The hard work as far as graphics card goes is dealing with 3D images. A faster clock speed, preferably edging towards or above the 500MHz mark, will handle this better than a slower clock speed.

The display connector is really determined by your monitor. Nearly all graphics cards have a VGA connector, which will fit most monitors. If you're running a TFT screen, though, you may find it supports a digital connection for higher quality, so some boards come with a DVI port to support this. Also, some graphics cards support more than one monitor at a time, and so have more than one connection on the card itself.

DirectX support involves specific drivers produced by Microsoft to get the most out of gaming on a PC. The latest boards are designed to make the most out of the latest version of DirectX. As you'd expect, older boards were designed to maximize older versions of DirectX, so while they'll still work with the new version, they won't eke out as much performance.

Other options that tend to be offered with some boards include S-Video and composite connections. These are useful for outputting to another screen, and for video capture. Incidentally, if video editing is a key reason for your purchase, then the likes of the ATI All-In-Wonder boards come with a small price premium but are designed for this kind of use (and come loaded with the features of the board they're based on - e.g. an ATI Radeon 9800 All-in-Wonder is a 9800 board with added features). Further added sweeteners can include the likes of free games and television antennae input.

We've saved the graphics processor for last, as ultimately it draws us back to the question at the very start; namely what do you want a new graphics adapter for? The two most prominent graphical processors are the GeForce FX series from Nvidia and the Radeon series from ATI. Currently, for high end gaming, ATI's Radeon series has a slight edge and ATI boards further down the line seem to be offering slightly better value for money. It's swings and roundabouts in this market though, and this is a scenario that could change quite quickly.

If it's a more basic board you're after, one that will struggle to play the latest titles at high frame rates, then you can pick up boards from the bottom of the GeForce FX and Radeon lines from around $100. These will happily work with the majority of PC-related tasks, complaining only when you're doing something really graphically intensive. If you really want to save money, then earlier generations of Radeon and GeForce boards stretch back many years and infest the second hand market.

That's covered the basics of buying a graphics board. This is designed to be an overview guide, and so hasn't touched on everything. However, the information here, combined with the latest graphics card reviews on this site, should help you make an informed choice.