How to adjust color Depth on Ubuntu 18.04, color transitions are not very smooth?

Question

linux

Installed Linux Ubuntu 18 on laptop - i7 7gen, Gtx950m.
Same problem with Mint 18 and Ubuntu 16.
Tried running nvidia control panel there are three buttons.
How do I set the normal color depth to display colors well? what drivers need to be installed?
There is no xorg.conf file anywhere in the file system