Well what version of unity do you have ? Second if you think a light weight desktop enviroment will make your game run faster than, you can install the Lubuntu xubuntu environment inside ubuntu. Lubuntu is the most light weight. You can use their environment instead of unity. However, unity will still be on the system, just not in use.
I currently have xubuntu (second lightest weight) , and am running it alongside unity, which is unstable, but really beautiful. If you prefer completely getting rid of unity and want to run the LXDE desktop,you’ll have to do some extra steps.
Try as many as you want.
Different environments commands
sudo apt-get install ubuntu-desktop
sudo apt-get install kubuntu-desktop
sudo apt-get install xubuntu-desktop
sudo apt-get install Lubuntu-desktop
Best
is very subjective and off topic here as noright
answer can be given, please see askubuntu.com/help/dont-ask Of course a light desktop (LXDE, XFCE, openbox) has better performance (uses less graphics ram / system ram) but the difference is negligible on anything but old computers and laptops. A modern environment (Unity, Gnome, KDE) will work best on a powerful system due to optimization. Side note, Steam runs better for me on Ubuntu Unity than Steam OS.gnome-session-flashback
to log in to a lighter DE having not too many new dependencies.