AMD definitely surprised me, and pretty much everybody else with their new products. I neither expected such a big performance increase, nor many of the other new features that AMD has put in their card. Looking at pure performance numbers, one has to admit that AMD did not claim the performance crown this time, their HD 4870 X2 and the NVIDIA GTX 295 are still faster. However, those are dual GPU cards, AMD's dual HD 5870 dubbed "Hemlock" will be out later this year to shatter all performance records we've seen so far.
Not only performance increased, AMD has also kept a tight lid on power consumption and die size didn't increase that much either, thanks to the 40 nm production process. I find the power consumption improvements very impressive. Especially in idle, the card is one of the most efficient cards you can find on the market today - and you still have all its rendering power just a click away. Under load the power draw is higher, but not nearly as high as performance numbers would suggest when applied to the last generation of cards. Looking at Performance per Watt, the Radeon HD 5870 leads by 23% over the next closest card, the GTX 295. While it is not the only improvement, a large power hog could be tamed by clocking down the GDDR5 memory when it is idle. Past cards had GDDR5 too, but due to the complex clocking mechanisms it wasn't possible to change the clock without an annoying flicker that would confuse users. Now the flicker is so short that it can be hidden between the monitor refresh intervals, enabling downlocking of GDDR5 in idle.
This latest generation of ATI graphics cards also brings support for DirectX 11, which includes a state of the art tesselation engine and support for DirectX Compute. Another area where we saw improvements are the multimedia features. The integrated audio device that is used for HDMI audio is now at HDMI 1.3a which means support for several new audio formats. As far as I know this puts the audio capabilities of the HD 5800 Series on par with anything that any external sound card can provide, making it an ideal choice for a media PC system.
Even though AMD has paid great attention to power, noise levels are not as low as I'd wished for. In idle the card's noise levels are very acceptable, but the idle temperatures are so low that I see no reason why the card couldn't be quieter and run a bit warmer. Under load the card gets fairly loud, but considering the performance, I'd say it's doing alright. Here again, some fan tweaking can give you higher temps and less fan noise if you want.
Finally, let's talk about your hard earned money. While not insanely expensive, those new cards can not claim the price/performance throne. They are high-end cards and that itself comes with a price premium. Being brand-new and having all the latest and greatest features adds a few dollars to the price tag, too. Still, I don't find the cards terribly expensive considering what they offer. If you are looking for the best deal on the market right now, you should look at other products like the HD 4870 which comes at extremely competitive prices at the moment. Also I already heard rumors that AMD's MSRP pricing will not hold for long and we'll soon see two digit $ price drops. Let's hope AMD has enough stock of these cards to supply all the gamers that can't wait to hold one in their hands now.