AMD Launches Radeon R9 280 Midrange Graphics Card For Gamers
The Radeon R9 280 is essentially a tweaked and reborn (not rebadged) Radeon HD 7950 but with faster clocks, higher watt tolerance, and a lower price tag at launch. Like the older card, the newer R9 280 is built around AMD's 28nm Tahiti GPU. It has 1,729 stream processors, 112 texture units, 32 ROPs, and 3GB of GDDR5 memory running at 5GHz on a 384-bit bus.

Compared to the 7950, the newer part has a higher clockspeed of up to 933MHz versus up to 925MHz. And whereas the older part had a Typical Board Power rating of 225W, the R9 280 is rated for 250W, which could indicate improvements to the silicon or better chip binning (we're speculating here).
Several of AMD's fancy technologies are present and accounted, such as full support for Mantle, OpenGL 4.3, and DirectX 11.2, along with PowerTune, CrossFire, and Eyefinity technologies.

In terms of performance, we have yet to get our hands on the card and run it through some benchmarks, but according to AMD's own evaluation, it will consistently outperform the GTX 760 at 2560x1600 in games like Metro 2033, Tomb Raider, and Battlefield 4.
AMD says the Radeon R9 280 will be available in the first week of March for $279, with wider availability expected in the second week for March.