Verdict: Two of ATI's fastest GPUs on one card.
Nvidia's GeForce 7950 GX2 graphics card used two GeForce 7-series GPUs to great effect, and ATI is hoping to emulate this success with its Radeon HD 3870 X2 card. Under the massive heatsink are two ATI HD 3870 GPUs but, unlike the GeForce 7950 GX2, there's only one circuitboard. MSI has also applied a further overclock to its oddly named R3870X2-T2D1G-OC, boosting both GPUs to 850MHz.
Measuring 10.5in long, the card's PCB has the same dimensions as the hefty Nvidia GeForce 8800 Ultra, albeit without the overhanging fan. The large, dual-slot cooler is framed by thick red metalwork that wouldn't look out of place on a Tonka truck, and it's no surprise that the card weighs a monumental 1.1kg. As a result, you should certainly take care to screw in the card properly when installing it. Under load, some of this metalwork becomes too hot to handle. This is indicative of the power consumed by the card - our test system drew a massive total of 426W (peak) with the T2D1G installed, 104W more than it did with a standard Radeon HD 3870 installed.
Looking at the underside of the card, you can clearly see where the two GPUs are located, and the traces to each GPU's 512MB of 900MHz (1.8GHz effective) GDDR3 memory. The T2D1G, like all Radeon HD 3870 X2 cards, has two power sockets, one 8-pin and one 6-pin, which point directly downwards.
The two GPUs on the PCB are linked by a third silicon chip, which acts as a high-bandwidth T-junction that shunts data in, out of and around the card. This bridge chip is only PCI-E 1.1-compliant, but ATI says it's fine for the work it's doing. A Radeon HD 3870 X2 card will therefore only be PCI-E 2.0-compliant if you turn off CrossFire, a feature currently missing from the driver. Like all Radeon HD 3870 X2 cards, the T2D1G has only one conventional CrossFire bridge connector, so you can only CrossFire a maximum of two cards.
You'd naturally expect a £275 graphics card to offer massive performance at high resolutions. It was therefore very disappointing that the T2D1G performed badly in Need for Speed: Pro Street, the least demanding game of our three benchmark games. At 1,680 x 1,050, the card struggled, only managing a minimum frame rate of 25fps. A Radeon HD 3870 (with its slower-clocked, single GPU) can comfortably handle our 1,920 x 1,200 test at a minimum of 30fps, so bugs in the BETA driver are obviously to blame.
Buggy drivers are also to blame for the poor Call of Duty 4 results - even £120 cards can manage 27fps in our 1,680 x 1,050 test, while the T2D1G wasn't fast enough to be officially playable at any of our test resolutions. However, we noticed that if we exited to the game menu for a few seconds after loading our test level, and then rejoined the game and tested as normal, we saw an increase of roughly 60 per cent in the frame rate. To publish these 'workaround' scores would have been unfair to other cards, however, as we'd be changing how we test to suit the product being tested. This would be the equivalent of not testing with AA if we thought that a card suffered badly from having to calculate this effect.
The T2D1G delivered slightly more favourable results in Crysis. In the 1,680 x 1050 test, the card scored a 14fps minimum and a 21fps average compared to the 11fps minimum and 15fps average of the Radeon HD 3870. This means that the T2D1G is around 40 per cent faster than the single-GPU Radeon HD 3870 in this game, but it still isn't fast enough to play the game at any of our test settings.
Given that the MSI's GPU overclock from 825MHz to 850MHz is only a 3 per cent increase, we wanted to see how much further we could push the T2D1G. Unfortunately, the Overdrive tool in the BETA Catalyst driver only allowed us to squeeze another 28MHz out of the GPUs and an extra 55MHz out of the memory. This provided a 1fps improvement in the Call of Duty 4 scores.
Conclusion
With a price tag of £275, the MSI R3870X2 T2D1G is only £15 more expensive than the cheapest standard-clock Radeon HD 3870 X2. However, the card boasts a modest factory overclock, which would be easy to perform yourself.
More importantly, we'd wait for driver updates to appear before considering buying any Radeon HD 3870 X2 card, as there are clearly significant problems in that department. In the meantime, buying the fastest single-GPU card you can afford is a much safer bet.
