6-Way Desktop Comparison On Linux Mint 17
Cinnamon, GNOME Shell, Xfce, MATE, and LXDE were running close to the same speed but KDE 4.13.0 in its stock Linux Mint 17 / Ubuntu configuration was slower than the rest. It's worth noting that KDE is still defaulting to using window decorations on full-screen windows; as said numerous times, we focus on the out-of-the-box experience for the most part as it's what the vast majority of Linux desktop users will encounter and that only a small percentage of Linux users go about extensively tweaking their system, etc.
With the Intel HD Graphics 4000 at least with the modern open-source driver stack, there wasn't too much difference to note when running these full-screen 3D/OpenGL Linux games.