Product Reviews

When nVidia launched its GeForce 7800 range a few months ago, its partners had lots of stock ready to fly off the shelves, putting the company well ahead of ATI. The wait for ATI's response is over. Sapphire's X1800XT is priced at the same level as the GeForce 7800 GTX, and ATI wants it to be top of every gamer's list.

The X1800XT is a single-slot card cooled by a single fan. It's also CrossFire ready, so you can add a second graphics card to increase performance.

However, it has some limitations. You need an Intel i955X or Radeon Xpress 200 motherboard with two PCI-E x16 slots; these are not widely available and quite expensive. You also need a CrossFire master card, which has a special DVI connector on it. At the time of writing, there were no X1800XT master cards available. This gives nVidia the edge when it comes to high-end performance, as its SLI motherboards and cards are available now.

The new nVidia SLI boards use two PCI-E x16 lanes for faster transfer rates, while ATI's

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CrossFire uses two PCI-E x8 lanes for its dual-card system. Dual-card systems are expensive and not for everybody, so it's important to see how well the X1800XT stacks up against the competition.

ATI's card is different in design to nVidia's. The X800XT has 16 pixel pipelines; nVidia's GeForce 7800GTX has 24. ATI has squeezed impressive clock speeds out of the chip; the core runs at a lightning-fast 625MHz, while the 256MB GDDR2 memory runs at 750MHz (1.5GHz effective). ATI has implemented Shader Model 3.0 and has an efficient processing engine. When playing games that support the technology, you'll see better effects and better-looking scenes at smoother frame rates.

In our benchmarks, the card scored 11,458 in 3DMark03 at 1,024x768 and 5,199 at 1,600x1,200 with 4xFSAA. It is faster than the GeForce 7800GTs we've seen, but slower than the 7800GTX. Its Doom 3 score of 71.4fps, while good, was a long way behind that of nVidia's GeForce 7800GT. This is because the current drivers don't handle OpenGL games such as Doom 3 very well. ATI gave us a patch to improve OpenGL performance, which it will incorporate into the next driver release. With the patch, test results increased to 92.7fps, which is still behind nVidia's GeForce 7800GT and 7800GTX.

Most games use DirectX, so you'll get excellent graphics performance when playing these titles. However, some new games will use Doom 3's engine, so nVidia looks set to stay on top there.

The X800XT is a good card, but until games are written to take advantage of its architecture we're unlikely to see the best of it.