What causes screen tearing?
Your GPU renders frames as fast as it can. Your monitor refreshes at a fixed rate (say, 144Hz - once every 6.9ms). When the GPU sends a new frame while the monitor is partway through drawing the previous one, the monitor stitches together the bottom of the old frame and the top of the new one. The result is a horizontal seam where images do not align - screen tearing.
Tearing is most visible in:
VSync - the original fix
VSync forces the GPU to hold completed frames until the monitor's next refresh. No frame starts scanning until the current one finishes. Tearing is eliminated.
The cost: When your GPU cannot maintain the target frame rate, VSync drops to the next lower divisor (from 144fps to 72fps, then 36fps). This creates a jarring stutters when framerate drops slightly below the sync rate. Input lag also increases because the GPU must buffer frames to stagger delivery.
Adaptive sync - the modern solution
FreeSync (AMD) and G-Sync (NVIDIA) let the monitor's refresh rate follow the GPU frame output. The monitor waits for each frame (within a range, typically 40–240Hz). No tearing, because the refresh never fires mid-frame. No VSync stutter, because the refresh rate flexes to match the GPU rather than forcing a fixed cadence.
This is the best solution for most gaming setups. See our G-Sync vs FreeSync guide for details on which standard to use.
When your framerate is above your monitor's max
Adaptive sync only eliminates tearing within its variable refresh range. If your GPU outputs 300fps on a 240Hz monitor, tearing will still occur. Solutions:
Testing for tearing
Use the Motion Test tool on this site. Set a horizontal sweep and watch for horizontal splits across the moving element. If you see tearing, enable adaptive sync in your GPU drivers and monitor OSD.