I have recently installed Ubuntu 16.04 with the 340.x driver using a Quadro NVS 420 (rev a1).
I am experiencing slow graphic response (after turning off animations, etc, under compiz) and periodic short freezes (10-20s).
I have the nvidia-bugreport output, but no apparent way to attach here.
Additionally, it does not seem possible to set screens to rotated in nvidia-settings.
Thank you for your help,