In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GT 640 Gigabyte OC 2GB Edition are noticeably better than the AMD Radeon R7 240 2GB.

The GT 640 has a 320 MHz higher core clock speed and 12 more Texture Mapping Units than the R7 240. This results in the GT 640 providing 19 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 GT 640 has a 320 MHz higher core clock speed and 8 more Render Output Units than the R7 240. This results in the GT 640 providing 11 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 R7 240 was released over a year more recently than the GT 640, and so the R7 240 is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the GT 640.

The GeForce GT 640 Gigabyte OC 2GB Edition and the Radeon R7 240 2GB have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The memory bandwidth of the GeForce GT 640 Gigabyte OC 2GB Edition and the Radeon R7 240 2GB are the same, which means the GT 640 and the R7 240 have equal limitations when it comes to graphical data transfer.

The GeForce GT 640 Gigabyte OC 2GB Edition has 384 Shader Processing Units and the Radeon R7 240 2GB has 320. However, the actual shader performance of the GT 640 is 403 and the actual shader performance of the R7 240 is 212. The GT 640 having 191 better shader performance and an altogether better performance when taking into account other relevant data means that the GT 640 delivers a slightly smoother and more efficient experience when processing graphical data than the R7 240.

The GeForce GT 640 Gigabyte OC 2GB Edition requires 65 Watts to run and the Radeon R7 240 2GB requires 30 Watts. We would recommend a PSU with at least 350 Watts for the GT 640 and a PSU with at least 400 Watts for the R7 240. The GT 640 requires 35 Watts more than the R7 240 to run. The difference is significant enough that the GT 640 may have a slight adverse affect on your yearly electricity bills in comparison to the R7 240.