Sapphire Radeon HD 4870 X2 review

In Labs, Shopper 248, we reviewed two graphics cards based on ATI's latest chipsets: the 4850 and 4870. Both were fast and good value. Indeed, Sapphire's HD 4850 won our Best Buy award.

However, neither the 4850 nor 4870 can match the speed of Nvidia's most powerful cards: the GeForce GTX 260 and GTX 280. The HD 4870 X2 is ATI's latest card, and aims to rectify the situation with a pair of HD 4870 graphics processors on a single board. It replaces the dual-processor 3870 X2 as ATI's top-of-the-range graphics chipset, and Sapphire's graphics card is the first we've seen to have two 4870 processors.

The Radeon HD 4870 X2 is a dual-slot card and, at 270mm, very long, which means that you'll need a large case to accommodate it. You'll also need a very modern power supply with one six-pin and one eight-pin PCI Express connector.

The HD 4870 X2 has an impressive specification. The two processors run at 750MHz, and each has access to 1GB of GDDR5 memory, so there's a huge 2GB of RAM on board; the single-chip 4870 has only 512MB, and Nvidia's GTX 280 has 1GB. The two processors are joined by a faster PCI Express bridge than on the 3870 X2, with a maximum bandwidth of 5GB/s instead of 2.5GB/s.

Despite its size and power, the 4870 X2 was fairly quiet when running our benchmarks. We compared it with a Zotac GeForce GTX 280 AMP Edition, which is an overclocked version of the standard Nvidia GTX 280 card and, at £330, costs about the same as the 4870 X2. There was a marked difference in performance between the cards, depending on which test we were running. In Crysis at 1,680x1,050 with 4x anti-aliasing and detail set to High, the 4870 X2 was marginally slower, with 34fps compared to the GTX 280's 36.7fps. In Call of Duty 4 at 1,680x1,050 with 4x anti-aliasing, the ATI card was far faster, managing 84.2fps compared to 64.2fps. Both games are playable at these settings, so you'll be able to enjoy the latest games on a 22in monitor with close to maximum quality settings.

However, 3DMark Vantage really highlighted the difference between the cards. At our custom settings of 1,680x1,050 with 4x anti-aliasing, the GTX 280 managed 7,125, but the HD 4870 X2 scored a huge 8,899, which is the highest score we've seen. 3DMark Vantage may be a synthetic benchmark and not a real game test, but it's indicative of a graphics card's raw power and how well it may fare in future titles.

Like Nvidia's GTX 280, Sapphire's HD 4870 X2 is very quick, very large and very expensive. There's little to choose between them, but its strong performance in 3DMark Vantage suggests the 4870 X2 may have the edge in future titles. However, we're not convinced that it's quick enough to be worth nearly three times the price of Sapphire's Radeon HD 4850.