In terms of overall gaming performance, the graphical capabilities of the AMD Radeon RX 540X 4GB Mobile are massively better than the AMD Radeon HD 8850M.

The RX 540X has a 499 MHz higher core clock speed but 8 fewer Texture Mapping Units than the Radeon HD 8850M. The lower TMU count doesn't matter, though, as altogether the RX 540X manages to provide 11 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 RX 540X has a 499 MHz higher core clock speed than the Radeon HD 8850M and the same number of Render Output Units. This results in the RX 540X providing 8 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 RX 540X was released over three years more recently than the Radeon HD 8850M, and so the RX 540X is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the Radeon HD 8850M when running the latest games.

The RX 540X 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 RX 540X also has superior memory performance overall.

The Radeon HD 8850M has 32 GB/sec greater memory bandwidth than the RX 540X, which means that the memory performance of the Radeon HD 8850M is noticeably better than the RX 540X.

The Radeon RX 540X 4GB Mobile has 512 Shader Processing Units and the Radeon HD 8850M has 640. However, the actual shader performance of the RX 540X is 624 and the actual shader performance of the Radeon HD 8850M is 496. The RX 540X having 128 better shader performance and an altogether better performance when taking into account other relevant data means that the RX 540X delivers a noticeably smoother and more efficient experience when processing graphical data than the Radeon HD 8850M.

The RX 540X transistor size technology is 14 nm (nanometers) smaller than the Radeon HD 8850M. This means that the RX 540X is expected to run slightly cooler and achieve higher clock frequencies than the Radeon HD 8850M.

The Radeon RX 540X 4GB Mobile requires 50 Watts to run and the Radeon HD 8850M requires 45 Watts. We would recommend a PSU with at least 350 Watts for the RX 540X. The RX 540X requires 5 Watts more than the Radeon HD 8850M to run. The difference is not significant enough for the RX 540X to have a noticeably larger impact on your yearly electricity bills than the Radeon HD 8850M.