I had the FX 9590 with ASUS board before and the game was always a bit laggy, especially on ultra settings. Everyone said the game is not optimised and it doesn't matter if you have better hardware. Then everyone also said, I should get an Nvidia GPU instead of my AMD 390X.
After setting up my system with the AMD 1800X and MSI 370X Titanium, the game runs like hell. Still using my AMD 390X
Running the CPU-Z stresstest in the background makes the game run like on my FX 9590:
The system is still fully responsive only the game lags a bit.
This is not the heaviest scenario, but on my old CPU it would have lagged at least at months end when the costs are calculated.