AMD's new Radeon R9 280X Series is based on the AMD HD 7970 GHz design, but probably comes with slightly reduced clocks to keep power draw at "saner" levels. So there is really nothing new overall, yet the card will definitely end up being a good choice for gamers because of its competitive price. In our testing, we found the ASUS R9 280X DC II TOP, which is overclocked out of the box, to beat the GTX 770 by 2%. Against the HD 7970 GHz Edition, the difference is 5%. AMD's latest 13.11 Beta drivers include new performance optimizations for games, though, which helps the card achieve these results. It is also nice to see a memory clock on the card—it provides a quick and easy performance advantage many other board partners overlook.
ASUS has reused the large DC II cooler from their GeForce GTX 780, which was a wise choice. The cooler handles the heat output of the card with ease, but tends to be a bit too noisy. This is not an issue of the cooler itself, but rather ASUS who failed to pick optimal fan settings. Temperatures are comfortably low, so it would have been easy to trade slightly higher temperatures for better fan noise.
Power consumption is roughly where you would expect it to be given the amount both HD 7970 and HD 7970 GHz cards consume—nothing of interest here. What does worry me is the very high power consumption during multi-monitor usage and media playback. AMD could have certainly improved those two facets with their latest generation, especially considering NVIDIA's huge lead here—the problem could be solved by picking smarter clock and voltage levels for these states.
The ASUS R9 280X DC II TOP is currently available online for $310, which is just a $10 price increase over the reference design. I find the price increase extremely reasonable given the overclock out of the box and the much better cooler. Looking at the options in this performance segment, $300 will get you a HD 7970 (non-GHz), which is slower and otherwise similar. The GHz Edition costs $375, making it more expensive for the same performance and the same feature set. At $300, NVIDIA has the GTX 670 with better power/heat/noise but 10% less performance. If you want to get the GTX 770, which is roughly as fast as the R9 280X, you'll have to cough up $380, a pretty large difference. So it looks like AMD's R9 280X is the best price/performance option in this segment right now, and that by quite a large margin. ASUS's R9 280X DC II TOP did leave a good impression. Its cooler might be a little noisy, but so far, this would be the R9 280X I would buy.