When i try to play XCOM: Enemy unknown, this happens
and as well with DotA 2. Steam version, reinstalled twice on both.
Settings manager -Additional Drivers -chose latest nvidia or novue driver System -Nvidia Xserver Settings -Check resolutions -Check GPU thermostat -make sure no other onboard gfx processors are running
It seems that OP of this thread at the nvidia dev forum had a similar issue, which lead me to this thread on AskUbuntu! with two (similar) solutions.
/var/logs/Xorg.0.log
for any errors (with (EE) in front of the lines)? Also, is this the native Steam client or the Windows one using Wine?