In terms of overall gaming performance, the graphical capabilities of the AMD Radeon R9 M365X 4GB are very slightly better than the AMD Radeon HD 8850M.

The R9 M365X and the Radeon HD 8850M have both the same core clock speed and the same Texture Fill Rate. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The R9 M365X and the Radeon HD 8850M have both the same core clock speed and the same Pixel Fill Rate. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The R9 M365X was released over a year more recently than the Radeon HD 8850M, and so the R9 M365X 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 R9 M365X has 2048 MB more video memory than the Radeon HD 8850M, so is likely to be much better at displaying game textures at higher resolutions. This is supported by the fact that the R9 M365X also has superior memory performance overall.

The R9 M365X has 32 GB/sec greater memory bandwidth than the Radeon HD 8850M, which means that the memory performance of the R9 M365X is noticeably better than the Radeon HD 8850M.

Both the Radeon R9 M365X 4GB and the Radeon HD 8850M have 640 Shader Processing Units. While the two GPUs have the same number of SPUs, the actual performance delivered by the Radeon HD 8850M is 496 and by the R9 M365X is 496. Knowing that the shader performance of the Radeon HD 8850M is superior, it is not necessary to examine the GPUs' respective Texture and Pixel Fill Rates.

The Radeon R9 M365X 4GB requires 50 Watts to run and the Radeon HD 8850M requires 45 Watts. The R9 M365X requires 5 Watts more than the Radeon HD 8850M to run. The difference is not significant enough for the R9 M365X to have a noticeably larger impact on your yearly electricity bills than the Radeon HD 8850M.