In terms of overall gaming performance, the graphical capabilities of the AMD Radeon RX 560X 4GB Mobile are massively better than the AMD Radeon HD 8850M.

The RX 560X has a 550 MHz higher core clock speed and 24 more Texture Mapping Units than the Radeon HD 8850M. This results in the RX 560X providing 50.2 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 560X has a 550 MHz higher core clock speed than the Radeon HD 8850M and the same number of Render Output Units. This results in the RX 560X providing 8.8 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 560X was released over three years more recently than the Radeon HD 8850M, and so the RX 560X 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 560X 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 560X also has superior memory performance overall.

The RX 560X has 80 GB/sec greater memory bandwidth than the Radeon HD 8850M, which means that the memory performance of the RX 560X is much better than the Radeon HD 8850M.

The Radeon RX 560X 4GB Mobile has 1024 Shader Processing Units and the Radeon HD 8850M has 640. However, the actual shader performance of the RX 560X is 1306 and the actual shader performance of the Radeon HD 8850M is 496. The RX 560X having 810 better shader performance and an altogether better performance when taking into account other relevant data means that the RX 560X delivers a massively smoother and more efficient experience when processing graphical data than the Radeon HD 8850M.

The RX 560X transistor size technology is 14 nm (nanometers) smaller than the Radeon HD 8850M. This means that the RX 560X is expected to run slightly cooler and achieve higher clock frequencies than the Radeon HD 8850M.

The Radeon RX 560X 4GB Mobile requires 80 Watts to run and the Radeon HD 8850M requires 45 Watts. We would recommend a PSU with at least 450 Watts for the RX 560X. The RX 560X requires 35 Watts more than the Radeon HD 8850M to run. The difference is significant enough that the RX 560X may have a slight adverse affect on your yearly electricity bills in comparison to the Radeon HD 8850M.