In terms of overall gaming performance, the graphical capabilities of the AMD Radeon HD 6750 PowerColor Low Profile Dirt3 1GB Edition are noticeably better than the Nvidia GeForce GT 640.

The GeForce GT 640 has a 202 MHz higher core clock speed but 4 fewer Texture Mapping Units than the HD 6750. The lower TMU count doesn't matter, though, as altogether the GeForce GT 640 manages to provide 3.7 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 GeForce GT 640 has a 202 MHz higher core clock speed than the HD 6750 and the same number of Render Output Units. This results in the GeForce GT 640 providing 3.2 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 GeForce GT 640 was released over a year more recently than the HD 6750, and so the GeForce GT 640 is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the HD 6750.

The GeForce GT 640 has 1024 MB more video memory than the HD 6750, so is likely to be much better at displaying game textures at higher resolutions. However, overall, the HD 6750 has superior memory performance.

The HD 6750 has 45.1 GB/sec greater memory bandwidth than the GeForce GT 640, which means that the memory performance of the HD 6750 is noticeably better than the GeForce GT 640.

The GeForce GT 640 has 384 Shader Processing Units and the Radeon HD 6750 PowerColor Low Profile Dirt3 1GB Edition has 720. However, the actual shader performance of the GeForce GT 640 is 346 and the actual shader performance of the HD 6750 is 252. The GeForce GT 640 having 94 better shader performance is not particularly notable, as altogether the HD 6750 performs better when taking into account other relevant data.

The GeForce GT 640 transistor size technology is 12 nm (nanometers) smaller than the HD 6750. This means that the GeForce GT 640 is expected to run slightly cooler and achieve higher clock frequencies than the HD 6750.

The GeForce GT 640 requires 65 Watts to run and the Radeon HD 6750 PowerColor Low Profile Dirt3 1GB Edition requires 86 Watts. We would recommend a PSU with at least 350 Watts for the GeForce GT 640 and a PSU with at least 450 Watts for the HD 6750. The HD 6750 requires 21 Watts more than the GeForce GT 640 to run. The difference is not significant enough for the HD 6750 to have a noticeably larger impact on your yearly electricity bills than the GeForce GT 640.