Sorry I haven'r seen you comment. As per your 1st question - I don't know that since I've only tried using 3 screens in 16.04, prior to that I had a desktop setup (11.04 to 14.04) with 2 screens without any problems, either using the nvidia drivers either the nouveau.
Regarding the nvidia propertiary drivers they don't work for me at all. Even when I did manage make them work the mini-display port didn't work so I could use only the screen in the HDMI port and the build-in screen. Only when I'm using the nouveau driver I'm able to use all the 3 screens together but with that annoying issue. ** Changed in: xorg (Ubuntu) Status: Expired => New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1590492 Title: Cursor is flickering or leaving annoying trails using 3 monitors To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1590492/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp