The 340.36-58 drivers seem to believe there is a 2nd video device CRT-0. 340.32 works ok. video card is a Quadro K2000M in a Lenovo W530. The Linux kernel is 3.13.58 on Ubuntu 14.04.1. I am also running Unity 7.2.2
340.32 does not see an extra video device CRT-0.
The windowing is very slow e.g. on 340.32 Chrome opens in about 1 second and on 340.46 thru 58 it takes 4 seconds to open. Dragging windows around is also quite a bit slower. Closing windows takes longer. When starting up at login the dialog window asking you to swip your finger is half hidden and located half way off the right side of the screen about 1 1/2 inches from the bottom.
Hope someone has some insight.