In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GT 650M Mac 1GB Edition are marginally better than the Nvidia GeForce 940MX 2GB.

The GeForce 940MX 2GB has a 222 MHz higher core clock speed than the GT 650M, but the GT 650M has 8 more Texture Mapping Units than the GeForce 940MX 2GB. As a result, the GT 650M exhibits a 1.9 GTexel/s better Texture Fill Rate than the GeForce 940MX 2GB. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The GeForce 940MX 2GB has a 222 MHz higher core clock speed than the GT 650M, but the GT 650M has 8 more Render Output Units than the GeForce 940MX 2GB. As a result, the GT 650M exhibits a 5.4 GPixel/s better Pixel Fill Rate than the GeForce 940MX 2GB. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The GeForce 940MX 2GB was released over three years more recently than the GT 650M, and so the GeForce 940MX 2GB is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the GT 650M when running the latest games.

The GeForce 940MX 2GB has 1024 MB more video memory than the GT 650M, so is likely to be much better at displaying game textures at higher resolutions. However, overall, the GT 650M has superior memory performance.

The GT 650M has 64.3 GB/sec greater memory bandwidth than the GeForce 940MX 2GB, which means that the memory performance of the GT 650M is much better than the GeForce 940MX 2GB.

Both the GeForce 940MX 2GB and the GeForce GT 650M Mac 1GB Edition have 384 Shader Processing Units. While the two GPUs have the same number of SPUs, the actual performance delivered by the GeForce 940MX 2GB is 644 and by the GT 650M is 346. Knowing that the shader performance of the GeForce 940MX 2GB is superior, it is not necessary to examine the GPUs' respective Texture and Pixel Fill Rates.

The GeForce 940MX 2GB requires 25 Watts to run and the GeForce GT 650M Mac 1GB Edition requires 45 Watts. The GT 650M requires 20 Watts more than the GeForce 940MX 2GB to run. The difference is not significant enough for the GT 650M to have a noticeably larger impact on your yearly electricity bills than the GeForce 940MX 2GB.