I just found this while trying to tweak performance in compizconfig – I’m currently running 14.04.3 with all of the available LTS-vivid packages and nvidia-346. The Unity desktop is much, much smoother after toggling off “copy to texture” in compizconfig during a session. There don’t seem to be any performance gains from starting up with it turned off; it has to be toggled mid-session.
Did some more testing and it turns out that when the desktop is in this state, hotplugging displays causes the session to crash back out to the login screen. So it’s not as usable as I hoped in all cases, but this is still really weird.
Can anyone duplicate this? Devs, any idea what might be going on? I know compiz is kind of a mess at this point, but curious. Super+W to move all windows is much, much faster now, and running something compiz-intensive like Google Hangouts no longer slows down the rest of the display when you have CPU+GPU to spare.