Monitors may begin flickering when they receive a signal of insufficient quality. There are a few potential fixes available that will help to improve the signal quality in order to eliminate flickering:
Replace Video Cables with high-quality Video Cables (e.g. upgrade DisplayPort 1.2 Cables to DisplayPort 1.4 Cables).
Use shorter Video Cables to reduce signal attenuation.
When possible, remove Video Adapters to use native Video Connection Types (e.g. go from VGA to VGA, or DisplayPort to DisplayPort)
For DisplayPort Monitors, try changing the DisplayPort Version on the Monitor. For information on how to change your Monitor Settings refer to the Manual from the Monitor Manufacturer.
Update the Drivers for the Computer’s GPU to the latest available from the Monitor Manufacturer.