Its not even noticable after you go 1440p or above resolution, since at resolution the R7, R6 pretty much performs the same (GPU bound at that point) but for a lower price than the competition. and honestly, anyone thats willing to buy them at those prices are most likely going to be gaming at 1440p or above. and…

Its the games engine thats the problem  (idTech5), i also own an FX-8370e (slower than the FX8350) paired with an R9 380X and this game engine really doesnt like AMD CPU and GPU (had the same problem with Wulfenstein), unlike Doom Vulkan mode (uses idTech6) wich runs like a boss on my machine with 60+ fps at 1440p…

This wouldnt have been a problem had they used the updated (heavily modified idtech5) idTech6 engine used in Doom that makes use of Vulkan, but im guessing they really didnt have the time to switch to the newer engine during the games development