In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GTS 450 v2 are noticeably better than the Nvidia GeForce GT 640.

The GeForce GT 640 has a 112 MHz higher core clock speed and 8 more Texture Mapping Units than the GTS 450. This results in the GeForce GT 640 providing 9.9 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 112 MHz higher core clock speed than the GTS 450, but the GTS 450 has 8 more Render Output Units than the GeForce GT 640. As a result, the GTS 450 exhibits a 4.6 GPixel/s better Pixel Fill Rate than the GeForce GT 640. 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 GTS 450, 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 GTS 450.

The GeForce GT 640 has 512 MB more video memory than the GTS 450, so is likely to be much better at displaying game textures at higher resolutions. However, overall, the GTS 450 has superior memory performance.

The GTS 450 has 58.1 GB/sec greater memory bandwidth than the GeForce GT 640, which means that the memory performance of the GTS 450 is much better than the GeForce GT 640.

The GeForce GT 640 has 384 Shader Processing Units and the GeForce GTS 450 v2 has 144. However, the actual shader performance of the GeForce GT 640 is 346 and the actual shader performance of the GTS 450 is 228. The GeForce GT 640 having 118 better shader performance is not particularly notable, as altogether the GTS 450 performs better when taking into account other relevant data.

The GeForce GT 640 transistor size technology is 12 nm (nanometers) smaller than the GTS 450. This means that the GeForce GT 640 is expected to run slightly cooler and achieve higher clock frequencies than the GTS 450.

The GeForce GT 640 requires 65 Watts to run and the GeForce GTS 450 v2 requires 106 Watts. We would recommend a PSU with at least 350 Watts for the GeForce GT 640 and a PSU with at least 400 Watts for the GTS 450. The GTS 450 requires 41 Watts more than the GeForce GT 640 to run. The difference is significant enough that the GTS 450 may have a slight adverse affect on your yearly electricity bills in comparison to the GeForce GT 640.