In terms of overall gaming performance, the graphical capabilities of the AMD Radeon RX 480X 8GB are noticeably better than the AMD Radeon R9 390X XFX Double Dissipation Black 8GB Edition.

The RX 480X has a 160 MHz higher core clock speed than the R9 390X, but the R9 390X has 48 more Texture Mapping Units than the RX 480X. As a result, the R9 390X exhibits a 31.8 GTexel/s better Texture Fill Rate than the RX 480X. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The RX 480X has a 160 MHz higher core clock speed than the R9 390X and the same number of Render Output Units. This results in the RX 480X providing 10.2 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 RX 480X was released over a year more recently than the R9 390X, and so the RX 480X is likely to have better driver support, meaning it will be more optimized for running the latest games when compared to the R9 390X.

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 Radeon RX 480X 8GB and the Radeon R9 390X XFX Double Dissipation Black 8GB Edition have the same amount of video memory, but are likely to provide slightly different experiences when displaying game textures at high resolutions.

The R9 390X has 384 GB/sec greater memory bandwidth than the RX 480X, which means that the memory performance of the R9 390X is massively better than the RX 480X.

The Radeon RX 480X 8GB has 2048 Shader Processing Units and the Radeon R9 390X XFX Double Dissipation Black 8GB Edition has 2816. However, the actual shader performance of the RX 480X is 2560 and the actual shader performance of the R9 390X is 2609. The R9 390X having 49 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 RX 480X.

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

The Radeon RX 480X 8GB requires 150 Watts to run and the Radeon R9 390X XFX Double Dissipation Black 8GB Edition requires 300 Watts. We would recommend a PSU with at least 500 Watts for the RX 480X and a PSU with at least 750 Watts for the R9 390X. The R9 390X requires 150 Watts more than the RX 480X 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 480X.