AMD has not promised too much when they stated that their HD 4870 X2 will be the fastest graphics card in the world. The HD 4870 X2 leads our testing with a 14% performance advantage over the NVIDIA GTX 280. However, this price will cost you. $549 is a huge amount of money which results in the worst performance per dollar ratio of all cards on the market today. Still, the performance a great achievement and gives users with deep pockets new options where to spend their money on. If you plan on gaming at 2560x1600 resolutions this card definitely has to be considered. For people gaming at more modest resolutions this card is almost too fast and too expensive. Even though AMD has managed to keep the power draw and heat output within reasonable levels, the power consumption is very high with a system peak power draw of over 380 Watt.
To me AMD's approach to power management is not as good as I expected. Even though the RV770 GPU offers several very nice ways to optimize power draw, AMD made a leap back to R600 times by using driver controlled 2D/3D mode switching. As a result of this the card will perform very poor in 2D and windowed 3D. In those modes the card will always run at 500 MHz core and memory - not 750/900 as in fullscreen 3D. Also in windowed 3D CrossFire is disabled which results in an even bigger performance hit. When you play any titles in windowed 3D the HD 4870 X2 will perform similar to a $100 graphics card. Let's hope a future driver update can fix this situation.
Under full load the two RV770 GPUs consume quite a bit of power which means that the cooling solution has to get rid of the excess heat somehow. Even though it does not sound like a leaf blower the card tends to be fairly noisy in 3D. AMD's CrossFire SidePort feature looks like it can offer some additional performance gains, but at this time it is disabled in the driver. Also AMD's card design (like any other multi-GPU solution) requires game specific profiles in the driver to perform at its best. Historically NVIDIA had an advantage here, but I am sure AMD's engineers are working hard to add CrossFire support to all the latest titles out there. Since NVIDIA acquired AGEIA PhysX, which is supported on all their recent cards, they are working hard on getting PhysX into all upcoming titles. Whether there will be a solution to run PhysX on ATI cards is unknown at this time.
Overall the AMD HD 4870 X2 offers amazing performance, but the product feels a bit unfinished. On the other hand this hints at solid improvements that could be seen in future driver versions. But the price has to come down first ...