Screen tearing is notorious in graphics applications, most prevalent in video games. The GPU runs at a particular frame rate and the display can have a separate frame rate. The synchronization between the GPU and the display can have issues when screen tearing or screen flickering occurs. Describing what the tearing looks like is important. Horizontal lines indicate that the GPU was in the middle of updating the previous frame with the next frame data, but the update was prematurely consumed by the display. Observe the pixel data around the tearing region and how far down the screen the tear is because this can indicate how severely the synchronization is being missed. Figure 2-1 is an example of screen tearing due to missing synchronization between the display and the graphics application.

Notice slightly above the halfway mark that there is an inconsistency in the triangles from a previous frame. This is the classic example of a screen tearing issue.

Figure 2-1 Screen Tearing Example