I’ve installed Nvidia driver 370.28 from ppa and faced with a problem that image quality is very poor.
I’ve tried older driver versions but the result is the same. There is no such problem with Nouveau drivers.
Laptop: Lenovo y510p
Graphical adapter: 01:00.0 VGA compatible controller: NVIDIA Corporation GK107M [GeForce GT 755M] (rev a1)
OS: Ubuntu 16.04 x64
Photo of the screen: