What is Screen Flickering and How to Fix It?
Back in the day of CRT monitors and TVs, flickering would be a common issue, which had little to do with today’s problems. Back then, a good slap would fix the misbehaving screen. Today, however, a good slap would probably break something, most likely the monitor stand.
Stilla Software Issue Dmac Solutions Possible Issues Display Adapter Display Driver Screen Flickering
Source: xbitlabs.com