So let's get our hands dirty. NVidia will try to sell you its GTX260 line, with prices starting from around £225, while point above £300 and you can shake hands with the GTX280 and 285. We're in serious performance territory here, and NVidia - in spite of the fierce competition in the budget and mid-range - is still a good horse to back where premium products are concerned. The money-no-object NVidia horse? The GTX 295, a staggeringly powerful graphics card, with a £400+ asking price to match.

ATI doesn't fight quite so hard at this end of the market, with its premium 4870X2 board effectively being the marrying together of a pair of HD 4870s on one card. You will, to be fair, still get a lot of performance out of it (although prices are north of £300). The rest of its premium line is made up of beefed-up versions of the HD 4870, and these can be picked up for an assortment of prices above £200, depending on how hard you want the specifications to be pushed.

Now we've had a look at a few of the products, let's take a look at a few further considerations you need to take into account before making your final choice.

AGP or PCI-E determines the kind of slot there is on your motherboard, and obviously you need a graphics card that will be compatible with it! The vast majority of modern motherboard and thus modern graphics cards support the PCI-Express slot (sometimes written as PCI-E or PCIe). This is the best choice for now; it has more bandwidth, and thus supports a faster throughput of information. In short, it can simply shift a lot more data per second.

AGP, however, ruled the roost for some time, and as a result there are many millions of AGP motherboards out there in the world. So there are many people looking to upgrade their graphics card without changing their motherboard too. Thus, even though they may have preferred to leave the AGP format behind, some graphics card manufacturers do still support it, and there's a strong second hand market, too.

That said, if you want to go anyway towards the ultimately impossible goal of future-proofing a system, it is worth upgrading to a motherboard with PCI-E support.

Do note that some very old systems may even rely on an older PCI slot. If this is the case with you, then your choices are likely to be limited to what you can find on the second hand market.

A high-end graphics card will not only need at least a strong 600W PSU in a PC to be able to function properly (and that's only a rule of thumb; in many cases the demands may be much higher), but it may also need a direct power connector. Without it, your graphics card won't be able to draw enough power directly from the motherboard alone, and thus will simply not run.

Power demands needs to be researched in advance of buying any powerful graphics card. Find out from your retailer of choice just how much power your card will need, and how it'll draw it. Will it need an extra connector? If so, what type? Find that out, and check whether your existing power supply can support that, otherwise you may have to figure a PSU into the budget as well.

An increasingly popular option in the graphics card market - and something that was being used as far back as the late 90s - is the combining of two graphics cards into one machine. This is done via SLI (if you're using NVidia products) or Crossfire (if it's ATI you're going with). With many motherboards now providing a pair of graphics cards slots to enable such an option, it's becoming gradually more popular.

The advantage is clear: with a second graphics card, you can get around another 70 percent in graphics performance as a rule of thumb, although obviously this varies on a game-by-game basis. And it doesn't have to be a premium-only idea. A pair of HD 3850s could offer grunt for the money that you'd struggle to match from a single card for the same amount of cash, for instance.

There are things to be aware of, though. It's worth checking compatibility between cards and with your motherboard before you shell out any money. Make sure, too, that you download all of the latest software drivers that you need. And make sure you take into account the additional power and cooling demands that will arise as a result of adding a second graphics card to your computer. Do a bit of homework there in advance, and you should be fine.