In terms of overall gaming performance, the graphical capabilities of the AMD Radeon HD 7850 are very slightly better than the Nvidia GeForce GTX 750 Ti.
The GTX 750 Ti has a 160 MHz higher core clock speed than the Radeon HD 7850, but the Radeon HD 7850 has 24 more Texture Mapping Units than the GTX 750 Ti. As a result, the Radeon HD 7850 exhibits a 14.2 GTexel/s better Texture Fill Rate than the GTX 750 Ti. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.
The GTX 750 Ti has a 160 MHz higher core clock speed than the Radeon HD 7850, but the Radeon HD 7850 has 16 more Render Output Units than the GTX 750 Ti. As a result, the Radeon HD 7850 exhibits a 11.2 GPixel/s better Pixel Fill Rate than the GTX 750 Ti. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.
The GTX 750 Ti was released over a year more recently than the Radeon HD 7850, and so the GTX 750 Ti is likely to have better driver support, meaning it will be more optimized for running the latest games.
The GeForce GTX 750 Ti and the Radeon HD 7850 have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.
The Radeon HD 7850 has 67.2 GB/sec greater memory bandwidth than the GTX 750 Ti, which means that the memory performance of the Radeon HD 7850 is much better than the GTX 750 Ti.
The GeForce GTX 750 Ti has 640 Shader Processing Units and the Radeon HD 7850 has 1024. However, the actual shader performance of the GTX 750 Ti is 937 and the actual shader performance of the Radeon HD 7850 is 793. The GTX 750 Ti having 144 better shader performance is not particularly notable, as altogether the Radeon HD 7850 performs better when taking into account other relevant data.
The GeForce GTX 750 Ti requires 60 Watts to run and the Radeon HD 7850 requires 130 Watts. We would recommend a PSU with at least 300 Watts for the GTX 750 Ti and a PSU with at least 500 Watts for the Radeon HD 7850. The Radeon HD 7850 requires 70 Watts more than the GTX 750 Ti to run. The difference is significant enough that the Radeon HD 7850 may have an adverse affect on your yearly electricity bills in comparison to the GTX 750 Ti.