In terms of overall gaming performance, the graphical capabilities of the AMD Radeon R9 390X XFX Double Dissipation Black 8GB Edition are significantly better than the Nvidia GeForce GTX 950 2GB.

The R9 390X has a 66 MHz higher core clock speed and 128 more Texture Mapping Units than the GTX 950. This results in the R9 390X providing 142.6 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 R9 390X has a 66 MHz higher core clock speed and 32 more Render Output Units than the GTX 950. This results in the R9 390X providing 37 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 GTX 950 was released less than a year after the R9 390X, and so they are likely to have similar driver support for optimizing performance when running the latest games.

Both GPUs exhibit very powerful performance, so it probably isn't worth upgrading from one to the other, as both are capable of running even the most demanding games at the highest settings.

The R9 390X has 6144 MB more video memory than the GTX 950, so is likely to be much better at displaying game textures at higher resolutions. This is supported by the fact that the R9 390X also has superior memory performance overall.

The R9 390X has 278.2 GB/sec greater memory bandwidth than the GTX 950, which means that the memory performance of the R9 390X is massively better than the GTX 950.

The Radeon R9 390X XFX Double Dissipation Black 8GB Edition has 2816 Shader Processing Units and the GeForce GTX 950 2GB has 768. However, the actual shader performance of the R9 390X is 2609 and the actual shader performance of the GTX 950 is 1232. The R9 390X having 1377 better shader performance and an altogether better performance when taking into account other relevant data means that the R9 390X delivers a massively smoother and more efficient experience when processing graphical data than the GTX 950.

The Radeon R9 390X XFX Double Dissipation Black 8GB Edition requires 300 Watts to run and the GeForce GTX 950 2GB requires 90 Watts. We would recommend a PSU with at least 750 Watts for the R9 390X and a PSU with at least 350 Watts for the GTX 950. The R9 390X requires 210 Watts more than the GTX 950 to run. The difference is significant enough that the R9 390X may have an adverse affect on your yearly electricity bills in comparison to the GTX 950.