Randomly, my monitor's image blanks for a moment then returns. I am facing this problem after installing Ubuntu 18.04 LTS as the only OS on this PC; id did not occur back when Windows was on it. I added:
sudo add-apt-repository ppa:oibaf/graphics-drivers
and updated then rebooted, but I still have the blanking problem.
I'm using DisplayPort output (see pictures below) cables as I was before installing Ubuntu, and didn't have this issue. Changing to 50Hz refresh did not help.