To put it simply, the display’s [progressive scan] time is fixed, while the graphics card’s drawing time is variable. This will cause the graphics card’s drawing speed to be faster than [progressive scan], which means that the graphics card ran away. Before the last picture on the monitor is drawn, the next picture will come out, so that the picture will be torn.
There are two ways to reduce screen tearing:
Lock frame by software
Through vertical synchronization technology, hardware support, such as: G-sync, FreeSync