GNU/Linux Desktop Survival Guide
by Graham Williams
Screen Tearing on X11
20201229 The screen display artefact called tearing is evident when, for example, changing from one window focus to another there is noise patterns displayed across the screen momentarily. It may also occur when using a video application. The effect is that parts of the screen appear to be torn from the rest of the screen. It occurs because the video is not in sync with the refresh rate of the display and may result from a transient issue in the video drivers. Thus it might be fixed on the next update or reboot.
A YouTube video can be run to test if you are seeing tearing.
Solutions may involve enabling the compositor, turn on full repaint as the vsync option, or moving to Wayland rather than X11.
A configuration option is to set the X11 variable TearFree (related to vsync) to True to ensure full screen repaints. To do so edit the file /etc/X11/xorg.conf.d/20-intel.conf, the 20 indicating the file ordering for processing of X11 configuration files, and the intel suggesting this is often an issue with Intel graphics.
Section "Device" Identifier "Intel Graphics" Driver "intel" Option "TearFree" "true" EndSection
This can slow down the screen refresh speed though so only use if the issue is not resolved by the driver itself.