Review Nvidia's GeForce 6800 GS chip is a respin of the 6800 GT. It's built on a 110nm process enabling it to offer higher clock speeds and, as such it has taken a lead over the cards based on ATI's X800 GTO. However, Sapphire is exclusively offering a part called the X800GTO². The 'squared' refers to the fact that this card's GPU has one 'quad' of pipelines that has been disabled, but that with a bit of jiggery-pockery from a BIOS flash and an overclocking tool, it can be turned from a 12-pipeline 400MHz card into a 540MHz 16-pipeline graphics card.

How so? This is because, unofficially at least, this card is to all intents and purposes an R480 - ie. an X850 XT. So why is ATI selling full-on X850 XT's as the lowly X800 GTO? Because X850 XTs were at one point very expensive to make, but as its manufacturing process matured costs came down, ATI is able to offer a much cheaper card by producing a full working R480 core and then disabling a pipeline quad. However, by thinly disguising the fact that it can be modded, ATI is able to generate buzz and a lot of mid-range sales, all pretty good for the bottom line. So while it says X800 GTO on the box, Sapphire might as well have written it in crayon over the X850 XT sticker. That said, there's no official support and BIOS flashing will void the warranty.

This means that instructions on how to modify the card aren't included in the box, but you can find them easily using a web search engine. The process should be trouble free, but I did run into problems. Once flashed, the card refused to generate a picture on our test system and it turned out that there was a rare incompatibility with our motherboard. After switching to another motherboard, the card booted fine and had successfully been upgraded 16 pipelines.

The card is a fairly regular looking thing. The heatsink spears to be copper rather than aluminium, to take care of the extra heat from the expected overclock. There's a power connector on the back, which is definitely necessary.

Once I'd flashed the card, I installed the popular ATI Tool utility to enable me to overclock the card. To see if the card lived up to the hype and being an impatient type, I didn't bother being cautious. I pushed the core and memory all the way up to X850 XT PE speeds - 540MHz for the core and 590MHz for the memory - and set it off to run. It did so without fuss for the entire run of benchmarks without image quality being affected. Again, there's no guarantee that this will be the case for every card. The cooler is also not as big as the one on the standard X850 XT PE, so good air-flow in your PC case is essential.

Our test system consists of an Asus A8N-SLI x16 motherboard, a 2.6GHz AMD Athlon 64 FX-57 and 2GBs of memory.

The scores we got from our card were very good. The tests I ran showed me that the modified card has the drop on the more expensive GeForce 6800 GS in most cases. Far Cry is a good example, with the GTO² besting the GS by a healthy 16.8fps at 1600 x 1200 with 4x FSAA and 8x AF. The lead in Half-Life 2 was even more pronounced with the modded and overclocked card hitting almost double the GS. However, Nvidia does have strong points. While the HDR in Day of Defeat: Source is designed to work with either Shader Model 2 or 3, it is faster on Nvidia, with the GS keeping up with the X850. Also, OpenGL has always been Nvidia's strong suit, and the GS matches the Sapphire card. The X850 doesn't lose, however, and that's an important point.

One feature that the GS does have that the Sapphire doesn't is Shader Model 3 support, but you have to ask yourself how likely you are to run in that mode with a card such as the GS, when really you'd want something faster.

The Sapphire Radeon X800GTO² is great news then for bargain hunters. It means that £150 and a little bit of work will buy you a very fast graphics card. Of course spending £20 or so extra will net you a 6800 GS or a X850 XT, but in most situations the modded Sapphire X800GTO² will outperform them both.

Verdict

For those in the know this is the best worst-kept secret in the graphics market right now. Since the price of X850 XTs has come down, it's not quite the bargain it once might have been, but it's still great value. If £150 is the kind of money you want to spend, this is a card worth hunting down.

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