In terms of overall gaming performance, the graphical capabilities of the AMD Radeon RX 480 4GB are marginally better than the AMD Radeon R9 390X PowerColor Devil 8GB Edition.

The RX 480 has a 20 MHz higher core clock speed than the R9 390X, but the R9 390X has 32 more Texture Mapping Units than the RX 480. As a result, the R9 390X exhibits a 32.3 GTexel/s better Texture Fill Rate than the RX 480. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The RX 480 has a 20 MHz higher core clock speed than the R9 390X, but the R9 390X has 32 more Render Output Units than the RX 480. As a result, the R9 390X exhibits a 34.6 GPixel/s better Pixel Fill Rate than the RX 480. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The RX 480 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 4096 MB more video memory than the RX 480, 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 166.4 GB/sec greater memory bandwidth than the RX 480, which means that the memory performance of the R9 390X is massively better than the RX 480.

The Radeon RX 480 4GB has 2304 Shader Processing Units and the Radeon R9 390X PowerColor Devil 8GB Edition has 2816. However, the actual shader performance of the RX 480 is 2917 and the actual shader performance of the R9 390X is 2633. The RX 480 having 284 better shader performance is not particularly notable, as altogether the R9 390X performs better when taking into account other relevant data.

The RX 480 transistor size technology is 14 nm (nanometers) smaller than the R9 390X. This means that the RX 480 is expected to run slightly cooler and achieve higher clock frequencies than the R9 390X.

The Radeon RX 480 4GB requires 120 Watts to run and the Radeon R9 390X PowerColor Devil 8GB Edition requires 275 Watts. We would recommend a PSU with at least 450 Watts for the RX 480 and a PSU with at least 750 Watts for the R9 390X. The R9 390X requires 155 Watts more than the RX 480 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 RX 480.