Screen Tearing

Screen tearing is a visual artifact in video display where a display device shows information from two or more frames in a single screen draw.

The artifact occurs when the video feed to the device isn't in sync with the display's refresh. This can be due to non-matching refresh rates—in which case the tear line moves as the phase difference changes (with speed proportional to difference of frame rates). It can also occur simply from lack of sync between two equal frame rates, in which case the tear line is at a fixed location that corresponds to the phase difference. During video motion, screen tearing creates a torn look as edges of objects (such as a wall or a tree) fail to line up.

Tearing can occur with most common display technologies and video cards, and is most noticeable in horizontally-moving visuals, such as in slow camera pans in a movie, or classic side-scrolling video games.