In terms of overall gaming performance, the graphical capabilities of the Nvidia GeForce GTX 580M SLI are massively better than the AMD Radeon R9 M365X 4GB.

The R9 M365X has a 5 MHz higher core clock speed than the GTX 580M, but the GTX 580M has 88 more Texture Mapping Units than the R9 M365X. As a result, the GTX 580M exhibits a 54.4 GTexel/s better Texture Fill Rate than the R9 M365X. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The R9 M365X has a 5 MHz higher core clock speed than the GTX 580M, but the GTX 580M has 48 more Render Output Units than the R9 M365X. As a result, the GTX 580M exhibits a 29.7 GPixel/s better Pixel Fill Rate than the R9 M365X. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The R9 M365X was released over three years more recently than the GTX 580M, and so the R9 M365X is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the GTX 580M when running the latest games.

The Radeon R9 M365X 4GB and the GeForce GTX 580M SLI have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The GTX 580M has 128 GB/sec greater memory bandwidth than the R9 M365X, which means that the memory performance of the GTX 580M is massively better than the R9 M365X.

The Radeon R9 M365X 4GB has 640 Shader Processing Units and the GeForce GTX 580M SLI has 768. However, the actual shader performance of the R9 M365X is 340 and the actual shader performance of the GTX 580M is 952. The GTX 580M having 612 better shader performance and an altogether better performance when taking into account other relevant data means that the GTX 580M delivers a massively smoother and more efficient experience when processing graphical data than the R9 M365X.

The R9 M365X transistor size technology is 12 nm (nanometers) smaller than the GTX 580M. This means that the R9 M365X is expected to run slightly cooler and achieve higher clock frequencies than the GTX 580M.

The Radeon R9 M365X 4GB requires 50 Watts to run and the GeForce GTX 580M SLI requires 200 Watts. The GTX 580M requires 150 Watts more than the R9 M365X to run. The difference is significant enough that the GTX 580M may have an adverse affect on your yearly electricity bills in comparison to the R9 M365X.