In terms of overall gaming performance, the graphical capabilities of the AMD Radeon R9 M270X are noticeably better than the AMD Radeon HD 8850M.

The Radeon R9 M270X has a 100 MHz higher core clock speed and 8 more Texture Mapping Units than the Radeon HD 8850M. This results in the Radeon R9 M270X providing 9.8 GTexel/s better texturing performance. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The Radeon R9 M270X has a 100 MHz higher core clock speed than the Radeon HD 8850M and the same number of Render Output Units. This results in the Radeon R9 M270X providing 1.6 GPixel/s better pixeling performance. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The Radeon R9 M270X was released over a year more recently than the Radeon HD 8850M, and so the Radeon R9 M270X is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the Radeon HD 8850M.

The Radeon HD 8850M and the Radeon R9 M270X have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The Radeon R9 M270X has 32 GB/sec greater memory bandwidth than the Radeon HD 8850M, which means that the memory performance of the Radeon R9 M270X is noticeably better than the Radeon HD 8850M.

Both the Radeon HD 8850M and the Radeon R9 M270X have 640 Shader Processing Units. The two GPUs are based on different architectures, but deliver an equivalent shader performance. To compare, we must continue to look at the memory bandwidth, Texture and Pixel Rates. In this case, the Radeon R9 M270X has 9.8 GTexel/s better Texture Fill Rate, 1.6 GPixel/s better Pixel Fill Rate, and 32 GB/sec greater memory bandwidth, so should have a noticeably faster performance than the Radeon HD 8850M.

The Radeon HD 8850M requires 45 Watts to run and the Radeon R9 M270X requires 50 Watts. The Radeon R9 M270X requires 5 Watts more than the Radeon HD 8850M to run. The difference is not significant enough for the Radeon R9 M270X to have a noticeably larger impact on your yearly electricity bills than the Radeon HD 8850M.