Screen tearing

It can also occur simply from a lack of synchronization between two equal frame rates, and the tear line is then at a fixed location that corresponds to the phase difference.

During video motion, screen tearing creates a torn look as the edges of objects (such as a wall or a tree) fail to line up.

[4] Alternatively, technologies like FreeSync[5] and G-Sync[6] reverse the concept and adapt the display's refresh rate to the content coming from the computer.

When such a movie is played on a monitor set for a typical 60 Hz refresh rate, the video player misses the monitor's deadline fairly frequently, and the interceding frames are displayed slightly faster than intended, resulting in an effect similar to judder.

Some graphics systems let the software perform its memory accesses so that they stay at the same time point relative to the display hardware's refresh cycle, known as raster interrupt or racing the beam.

In that case, the software writes to the areas of the display that have just been updated, staying just behind the monitor's active refresh point.

Depending on how far ahead one chooses to stay, that method may demand code that copies or renders the display at a fixed, constant speed.