In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GTX 650 1GB are very slightly better than the AMD Radeon HD 7750 1GB GDDR5.
The GTX 650 has a 258 MHz higher core clock speed and the same number of Texture Mapping Units as the HD 7750. This results in the GTX 650 providing 8.3 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 GTX 650 has a 258 MHz higher core clock speed than the HD 7750 and the same number of Render Output Units. This results in the GTX 650 providing 4.1 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 GTX 650 was released less than a year after the HD 7750, and so they are likely to have similar driver support for optimizing performance when running the latest games.
The GeForce GTX 650 1GB and the Radeon HD 7750 1GB GDDR5 have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.
The GTX 650 has 8 GB/sec greater memory bandwidth than the HD 7750, which means that the memory performance of the GTX 650 is marginally better than the HD 7750.
The GeForce GTX 650 1GB has 384 Shader Processing Units and the Radeon HD 7750 1GB GDDR5 has 512. However, the actual shader performance of the GTX 650 is 406 and the actual shader performance of the HD 7750 is 369. The GTX 650 having 37 better shader performance and an altogether better performance when taking into account other relevant data means that the GTX 650 delivers a slightly smoother and more efficient experience when processing graphical data than the HD 7750.
The GeForce GTX 650 1GB requires 64 Watts to run and the Radeon HD 7750 1GB GDDR5 requires 55 Watts. We would recommend a PSU with at least 400 Watts for the GTX 650 and a PSU with at least 400 Watts for the HD 7750. The GTX 650 requires 9 Watts more than the HD 7750 to run. The difference is not significant enough for the GTX 650 to have a noticeably larger impact on your yearly electricity bills than the HD 7750.