Sapphire Radeon HD 4850 X2 review

Twin-GPU graphics cards keep on coming, but not always to steal the performance crown. The latest from ATI is a dual version not of the top-end HD 4870, but its slightly slower sibling, the HD 4850.

It has two cores running at 625MHz, with each offering 800 stream processors and 1GB of RAM to make a truly meaty concoction. It's a real monster, too, a good centimetre longer than other X2 cards we've seen, and several inches longer than most motherboards are wide. The three-pin and four-pin power connectors are sensibly positioned on the side to allow you to actually reach them, but it'll still be a squeeze in many PCs.

With 2GB of RAM on the card, we went straight for a 64-bit Windows installation to make sure all of our 3GB of system RAM was recognised, but problems occurred immediately. At first Intel's X58 chipset driver didn't recognise it, then when we'd fixed that the latest ATI driver - the same Catalyst 8.11 supplied by Sapphire - failed to recognise the card at all.

The only way we could get it working was by rolling back to an earlier beta version of the same driver, which isn't the best start. Hopefully these teething problems will be fixed by Catalyst 8.12.

With the card finally up and running, we found it was inconsistent. At low settings it ran slower than a single HD 4850, scoring just 48fps in Crysis using medium settings and 30fps in Call of Juarez. When we pushed harder it improved, managing 44fps in Crysis at 1,680 x 1,050 and high quality settings, compared to 32fps of the single GPU card. At very-high settings and 1,920 x 1,200 it remained playable, averaging 29fps, again better than the HD 4850. And in Call of Juarez at High settings it reached 81fps, far beyond the 45fps of the standard card.

If you push it hard, as you'll surely do if you're willing to pay this much for a graphics card, you will see benefits. But is this high-end improvement worth two-and-a-half times the cost of the HD 4850, and just £50 less than a HD 4870 X2? Maybe when the driver issues are sorted that answer might be yes, but right now we'd have to say no.

Author: David Bayon