AMD successfully pulled off the seemingly impossible: they married two Radeon HD 6970 GPUs on one PCB. A year ago nobody would have thought such an engineering feat possible. Modern high-end GPUs are limited by the power they can draw and the heat that amount of power generates. It is impressive to see so much rendering power combined in the fairly small volume of a dual slot graphics card. As a result the Radeon HD 6990 is the fastest graphics card in the world, it is leading NVIDIA's GeForce GTX 580 by a comfortable 30% performance margin.
All this performance does have its downsides however, due to the high heat density, the cooler has to work hard to keep the card cool, which results in very high noise levels when fully loaded. In idle, fan noise is acceptable, but not that quiet when compared to other graphics cards. AMD's PowerTune technology helps keep the worst case power consumption in tests like Furmark down, but even in normal gaming, Performance per Watt is not as impressive as we have seen from previous AMD cards. What is really a big issue in my opinion is Blu-ray power consumption that seems excessively high with over 70 W. Operating temperatures of the card are reasonable and look well optimized. With around 85° there is even some headroom for additional overclocking. AMD offers a quick and easy hardware overclocking feature in form of their dual BIOS, but the loss of warranty that goes with it might turn off many users. In order to successfully do manual overclocking, one has to disable AMD's ULPS power saving technology, otherwise the overclocking attempts quickly end with a Windows Bluescreen. We saw about 10% overclocking potential on our card which is decent, given the already high power and thermal requirements of the design.
Due to AMD policy, the changes that ASUS could do the card are extremely limited. I really like the ASUS cooler design, it is clean and stylish. Instead of a plastic sticker, ASUS has glued a metal plate to the cooler which adds a feel of quality and also serves as heatspreader. Even though it was not included with our package, we expect ASUS to release a SmartDoctor version soon that supports the HD 6990 for overclocking and voltage increases.
Pricewise there are no big surprises, coming in at $699, the Radeon HD 6990 is expensive, but highest-end cards always came with a price premium. Unless you are gaming on a 30" or Eyefinity setups, the card seems a little bit overkill, especially when many new titles are console ports that use only DirectX 9. On the other hand, if you can afford the price tag and have the monitor estate, the HD 6990 seems to be a good alternative to a multi-GPU setup. NVIDIA will be releasing their own dual-GPU card later this month, so it might be wise to hold off with a purchase until all options are on the table.

Don't forget to check out our Powercolor HD 6990 CrossFire review to see how two of these monsters perform in a quad-GPU CrossFireX configuration.