In terms of overall gaming performance, the graphical capabilities of the AMD FireStream 9270 are noticeably better than the Nvidia GeForce GT 640.

The GeForce GT 640 has a 152 MHz higher core clock speed than the FireStream 9270, but the FireStream 9270 has 8 more Texture Mapping Units than the GeForce GT 640. As a result, the FireStream 9270 exhibits a 1.1 GTexel/s better Texture Fill Rate than the GeForce GT 640. 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 152 MHz higher core clock speed than the FireStream 9270 and the same number of Render Output Units. This results in the GeForce GT 640 providing 2.4 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 three years more recently than the FireStream 9270, and so the GeForce GT 640 is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the FireStream 9270 when running the latest games.

The GeForce GT 640 and the FireStream 9270 have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The FireStream 9270 has 80.3 GB/sec greater memory bandwidth than the GeForce GT 640, which means that the memory performance of the FireStream 9270 is much better than the GeForce GT 640.

The GeForce GT 640 has 384 Shader Processing Units and the FireStream 9270 has 800. However, the actual shader performance of the GeForce GT 640 is 346 and the actual shader performance of the FireStream 9270 is 390. The FireStream 9270 having 44 better shader performance and an altogether better performance when taking into account other relevant data means that the FireStream 9270 delivers a significantly smoother and more efficient experience when processing graphical data than the GeForce GT 640.

The GeForce GT 640 transistor size technology is 27 nm (nanometers) smaller than the FireStream 9270. This means that the GeForce GT 640 is expected to run slightly cooler and achieve higher clock frequencies than the FireStream 9270.

The GeForce GT 640 requires 65 Watts to run and the FireStream 9270 requires 160 Watts. We would recommend a PSU with at least 350 Watts for the GeForce GT 640 and a PSU with at least 600 Watts for the FireStream 9270. The FireStream 9270 requires 95 Watts more than the GeForce GT 640 to run. The difference is significant enough that the FireStream 9270 may have an adverse affect on your yearly electricity bills in comparison to the GeForce GT 640.