Radeon R9 260 (OEM) is an OEM only Graphics Card based on the Bonaire XTX core of the Graphics Core Next Architecture.

The Bonaire XTX Core has its roots on the Bonaire XT Core used on Radeon HD 7790. It offers 896 Shader Processing Units, 56 TMUs and 16 ROPs, on a 128-bit memory interface.
However and when compared to Radeon HD 7790, Radeon R7 260X has its central unit running at 1100MHz. Furthermore, its operating memory clock is significantly higher and of 1625MHz, leading to extra memory bandwidth.
Benchmarks indicate its performance is quite superior to its predecessors (Radeon HD 7770), but famous Radeon HD 7850 and its GeForce GTX 650 Ti Boost Edition still offer much more performance.
Expect to run most modern demanding games, such as Crysis 3 and Metro Last Light at high-settings, though a 1080p resolution will probably reduce your gaming experience and something more modest might be best suited.