In terms of overall gaming performance, the graphical capabilities of the AMD Radeon RX 490X 8GB are significantly better than the AMD Radeon R9 390X XFX Double Dissipation Black 8GB Edition.

The R9 390X has a 90 MHz higher core clock speed than the RX 490X, but the RX 490X has 208 more Texture Mapping Units than the R9 390X. As a result, the RX 490X exhibits a 192.2 GTexel/s better Texture Fill Rate than the R9 390X. 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 90 MHz higher core clock speed than the RX 490X, but the RX 490X has 64 more Render Output Units than the R9 390X. As a result, the RX 490X exhibits a 58.2 GPixel/s better Pixel Fill Rate than the R9 390X. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The RX 490X 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 Radeon RX 490X 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 490X, which means that the memory performance of the R9 390X is massively better than the RX 490X.

The Radeon RX 490X 8GB has 6144 Shader Processing Units and the Radeon R9 390X XFX Double Dissipation Black 8GB Edition has 2816. However, the actual shader performance of the R9 390X is 2609. The RX 490X having 3535 better shader performance is not particularly notable, as altogether the R9 390X performs better when taking into account other relevant data.

The RX 490X transistor size technology is 14 nm (nanometers) smaller than the R9 390X. This means that the RX 490X is expected to run slightly cooler and achieve higher clock frequencies than the R9 390X.

The Radeon RX 490X 8GB requires 250 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 600 Watts for the RX 490X and a PSU with at least 750 Watts for the R9 390X. The R9 390X requires 50 Watts more than the RX 490X to run. The difference is significant enough that the R9 390X may have a slight adverse affect on your yearly electricity bills in comparison to the RX 490X.