Recently, I have been having a few issues with a few games: once in a while, I like to play a bit of FPS to de-stress, and my frame rate was just abysmally low, what used to be a good 60 FPS went down to 20-30, leaving me with barely playable games, although these were great under Linux Mint 17.
After a bit of searching, I have found something interesting: if Google Chrome is running, the frame rate will be bad. If it is not, my games are back to normal. As Google Chrome uses the GPU for various tasks, I guess this was either due to a conflict (the two applications fighting for GPU resources) or Google Chrome setting some parameters that are detrimental to the games. Looking at Google Chrome's GPU status shows that a few features are either disabled or not available.