I tried a lot of desktop environments and I think KDE is the best one, games runs much better than GNOME while the desktop is so smart and many features… I really tried so hard GNOME but the UI sucks, it is slower running games, there are missing options very important for me that KDE has, so for me GNOME is a NO for working/gaming purposes.
But that’s the theory, when I run games on GNOME the games and desktop itself looks laggy, on KDE 4 I still noticed some lag while with KDE 5 I feel almost like playing on i3wm, with 3iwm you can run many games faster and with less lag than many Windows users (my Windows friends normally have more issues than me). While KDE 5 is my second-best option, there is no third for me. Or i3wm or KDE for gaming. And normally my PC specs stands higher than the recommended on many games (also new ones). If you can test it and provide some feedback would be great.