Radeon R9 255 (OEM) is an OEM only Graphics Card based on the Graphics Core Next architecture. It offers the Cape Verde PRX GPU.
The Cape Verde PRX GPU is a second revision of the Cape Verde PRO GPU used on famous Radeon HD 7750. It offers the same core configuration (512:32:16, SPs, TMUs, ROPs) and the same bus width interface - 128-bits, but the central unit is clocked at 930MHz (instead of 800MHz) and the operating memory clock runs at 1625MHz, instead of 1125MHz. Thus, the card offers superior shader performance and extra memory bandwidth. The PRX variant also offers DirectX 11.2 Support but not AMD's TrueAudio Technology due to not being a GCN 2.0 Core.
Due to the increased clock frequencies, the rated TDP board, despite not being known yet, should be higher than Radeon HD 7750 and close to Radeon HD 7770.
Its gaming performance is also not known yet. We will update this area once benchmarks become available.