I don't have a 4K monitor, but the following steps fixed video tearing with Kubuntu 16.04 on my Intel i7-2600k CPU with integrated Intel HD 3000 Graphics.
Edit /etc/environment and add the following lines: __GL_YIELD="USLEEP" KWIN_TRIPLE_BUFFER=0 KWIN_USE_BUFFER_AGE=0 Save the file and reboot. See the following link: Screen Tearing on Kubuntu 16.04 with Intel Drivers? https://askubuntu.com/questions/764302/screen-tearing-on-kubuntu-16-04-with-intel-drivers/774788 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1535447 Title: Intel Graphics 4K Screen Tearing To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1535447/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
