So, you know you need something that can run the latest games, but you're baffled by technical terms and haven't a clue what goes on inside your machine? The aim of this guide is to show you what to look for in a graphics card, to explain some of the more confusing terminology, and to help you make an informed purchase.

Basic Information

• Graphics cards (also referred to as Video Card, 3D Card, 3D Accelerator) is the part of your computer that produces the image on your computer's monitor.
• The graphics card is a modular component that slots into a designated area of your computer.
• Most computers are only capable of running one of these cards at any one time (with exceptions, which we'll read about later).
• Upgrading your graphics card will require you to remove your old one, and replace it with a newer model.
• Cards range in price. Typical low-end cards are £15-30. High end models can exceed £400.

Which one should you buy, and how much should you expect to pay?

• Key terms to look for: DirectX 10, GDDR3, HDCP, HD, DVI, SLI, Crossfire
• Target price range: £80 - £300

• Key terms to look for: DirectX 9, DVI, VGA, Dual Display
• Target price range: £15 - £40

• Key terms to look for: DirectX 10 (or 9), HDCP, HD, DVI, TV-Out, VIVO, TV Tuner, DVB-T
• Target price range: £40 - £200

Those of you whom don't fit into any of these categories (for example, the occasional gamer, or a family wishing to use a single machine) will need to consider a model that compromises cost and performance.

Graphics Card Type - AGP & PCI-E

Now that we have an idea of the type of graphics card you should be looking for, we need to consider the age of your computer.

Around 2002-2004, there was a big change in the way graphics cards are connected to computers, with the introduction of a technology called PCI-E (PCI Express).

Prior to this point, graphics cards were plugged into a slot called AGP (Accelerated Graphics Port). Put simply, PCI-E is simply a newer, faster type of slot that allows the use of more powerful graphics cards.

AGP Slot - Older and slower (and not always red)	PCI-E - Newer and faster (and not always yellow)

Because the slots are different shapes (and the technologies incompatible) you cannot use an AGP card with a newer (PCI-E) computer and vice-versa. This means you will need to buy whichever type of card is compatible with your system.

The depreciation of AGP also means that new AGP graphics cards are no longer made, and you will only be able to get so much performance out of your machine before you reach the limits of AGP technology. The latest games almost demand the use of a newer card, so it might be time to consider replacing your machine.

On the plus side, AGP graphics cards are now available in both the new and used market at very low prices as retailers clear their stock, and private sellers (for example, on eBay) whom have upgraded their computers try to sell off their older (but still powerful) graphics cards.

General Buying Tips

- Don't always rely on the more expensive graphics cards being more powerful. Whilst it's generally a good guide, you could always get caught out by retailers charging more than they should for a particular model.
- Watch out for price-drops. Competition between ATI & Nvidia means there's always a more powerful graphics card around the corner, and the release of a new, faster range will have an effect on the prices of other graphics cards.
- Some manufacturers offer high performance cards at low prices. Remember that this may be because the manufacturer does not offer the same level of service and support as others may do.
- Reviews on websites are a good way of finding out if a graphics card you have your eye on is actually any good, and for gauging prices. Cnet.com is a good place to start. There are plenty of printed computer magazines available too. Often these reviews cite benchmarks and in-game performance, which are a great way of comparing the relative performance of graphics cards.

Terminology

There is lots of other terminology that you may see or hear when looking for a graphics card.
Let's summarise the most important...

Direct X (8, 9 & 10)

This software handles the playback of media and games on your computer. Newer versions (the latest being DX10, which is only available in Windows Vista) provide improved visual effects and realism in games. Graphics cards are required to support Direct X features, and almost all modern graphics cards are advertised as being DirectX 9 or (more recently, DirectX 10) compliant.

Nvidia & ATI

These are simply the two largest graphics card technology producers. These companies design the components that go into graphics cards, but do not generally sell the finished product to consumers.

BFG, Connect3D, MSI, ASUS, Sapphire, etc

These are all companies that manufacture graphics cards based on Nvidia and ATI's reference designs. These are the companies that retail and provide support for the card that you buy. Some will offer 'overclocked' or 'tuned' versions of graphics cards that run faster than standard models. Also look out for manufacturer 'bundles' that include a few games with the card.

Memory (RAM/MB)

A component of the graphics card that temporarily holds textures (images) used in your games. The more of this supplied with the card, the better the general performance will be. For modern games, 256MB is about the minimum you should aim for. For office work and general computer use, this is of fairly low importance.

Pipelines, Resolution & Clock Speed

All of these are technical specifications that can be very confusing. As a general rule of thumb, the higher the number, the better the performance. When comparing two cards by specification, this can be a simple way of gauging performance, but benchmark results supplied by reviews can provide a more helpful impression of a graphics card's capabilities.

DVI & VGA (D-SUB)

These are types of connectors used to connect your monitor to your graphics card. DVI is a newer digital connection that provides a clearer image at higher resolutions. VGA is an older analogue connection that isn't quite as good. Whilst both will provide acceptable images, DVI is preferred. If your monitor's connector does not match your graphics card, you can purchase a cheap (£3-5) adaptor. Some cards will offer two connectors. This allows you to use two screens at once, which can very useful for office work or media production tasks.

Resolution

A measure of your graphics card's ability to output a video signal at a particular size (in pixels). Generally referred to in the format 1280x1024, but the numbers are often much higher.
Modern graphics cards are now all capable of producing extreme resolutions. You'd be hard-pressed to find a monitor that can display a native resolution higher than your graphics card can produce. As such, it isn't usually an important factor when choosing a graphics card.

SLI & Crossfire

As we've seen, most computers are only capable of using one graphics card at a time. However, some higher-end machines are designed to accommodate two (or more). Combining the performance of two cards will improve the smoothness of your games, but will not give you twice the performance. Many games are unable to utilise the extra performance effectively, and it's actually possible for a game to run slower on dual-card system, because of peculiarities in the way the game runs. The graphics card software will typically have various settings you can try to improve performance with two graphics cards.

SLI and Crossfire refer to the dual-card systems of Nvidia and ATI respectively. They are not inter-compatible, so you will need to check which system your computer supports (if either).

TV-Out, VIVO

Some graphics cards are designed to give you the option of connecting your TV to your computer. TV-Out signifies this functionality, and usually means the graphics card has an S-Video or component output. VIVO (Video in, Video out) means that the graphics card also has the ability to record video signals from your VCR, Satellite Tuner, Camcorder or DVD player. This is sometimes seen on models featuring an integrated TV Tuner.