FX 9590 will bottleneck the graphics cards in CPU intensive games. It is already a 5 year old CPU, which is based on an improved version of a 7 year old 32nm Bulldozer process.
If you want to do an AMD build, go for the AMD Ryzen 5 (1600/1600X) line of chips and get yourself just one powerful card. I would recommend a Fury X with a water cooler compared to two RX 480s in crossfire.
Why?
Because I have an FX CPU myself and even though they clock high they will only get you just enough performance for last year games, and stutter quite a bit in modern AAA games due to low single thread performance.
Right now the fastest build for gaming is
i7 7700K + GTX 1080Ti,
which is also the best build if you were to go Intel +NVidia.
If you...