Just a couple of weeks ago Nvidia announced its latest graphics chip, the GeForce GTX 580M, with the promise of delivering the best mobile gaming performance available anywhere. Well, AMD is now ready to challenge that claim. The company today announced the Radeon HD 6990M and is touting it as the new king of the hill.

Despite the name, the new Radeon is not based on the latest the Cayman architecture, nor it's packing dual-GPUs in a single card solution like its desktop counterpart. Instead, it features a full Barts core with all 1120 shaders enabled -- as opposed to 960 shaders for the HD 6970M, AMD's top mobile part prior to today's announcement. Core clock speeds have also been bumped to 715MHz, from 680MHz on the 6970M, while memory bandwidth remains the same at 115.2GB/s. The HD 6990M features 2GB of 3600MHz GDDR5 memory, instead of 1GB on the HD 6970M.

The closest desktop equivalent for the 6990M would be the HD 6870, which comes clocked 25% higher at 900MHz. In terms of features you get the now-standard DX11 support as well as HD3D (stereoscopic 3D) and OpenGL 4.1 support.

According to AMD's own internal benchmarks, the 6990M outperforms the Nvidia GeForce GTX 580M by about 20% on 3DMark Vantage and 3DMark11, and is anywhere from 5% to 20% faster in a bunch of games. AMD's presentation didn't include any battery life numbers, and considering its latest GPU doesn't support the same sort of automatic graphics switching as Nvidia's Optimus, it's likely that the green team still has the upper hand in this area.

AMD says the 6990M will be available starting today in the Alienware M18x, in both single and CrossFire configurations, while Clevo will also support the HD 6990M in their P170HM, P150HM, and X7200 notebooks.