iMac screen flickers
I have an iMac (retina 5K 27inch late 2015) that runs macOS Mojave 10.14.6. My graphic card is AMD Radeon R9 M390 2GB. In the last few months after using the iMac for a few hours or sometimes 30 min after restart the iMac screen starts to flicker and the only way to stop this is to shutdown or restart the iMac. In time I've noticed that the speed of flickering is increasing in its getting harder and harder to close the apps before restarting the iMac. Is anyone else experiencing the same problem?