You can read the full article with all the tested games, but needless to say this is strong evidence AMD has put so much effort into the drivers for the RX 500 series that the on paper slower RX 580 outperforms the on paper faster Fury X in DirectX 12 and Vulkan, while DirectX 11 is more or less equal.
And just to remind people, the Fury X has a -much- higher texture and pixel fill rate (39% and 57%, respectively), much higher single precision GFLOPS power (39%), and much faster memory with a much larger memory bus. The Fury-X should -NOT- be trumped by the RX 580 in any way, yet it is, up to 41% (in Wolfenstein II, Vulkan title).
https://www.wccftech.com/review/nvidia-geforce-gtx-1660-super-review-msi-gaming-x/
