What causes screen tearing in games?

The game swapping the display buffer to a new frame while the display is partway through reading the old one, so the screen shows part of two different frames with a visible tear line between them. This happens because frame presentation (buffer swaps) isn't synchronized with the display's refresh cycle, so swaps occur mid-refresh. It's most visible during motion.

Should I force vsync on to stop tearing?

No, offer it as an option. While vsync eliminates tearing, it adds input latency and can cause frame-rate stepping if the game can't keep up, so some players (especially competitive ones) prefer tearing over the latency. Give players the choice (vsync on/off) and support variable refresh rate where available, so they can balance tear-free rendering against low latency for their setup and preference.

How to Fix Screen Tearing in Your Game

Q: How do I fix screen tearing?

Enable vsync (vertical sync), which syncs buffer swaps to the display refresh so a new frame is only presented at the start of a refresh cycle, eliminating tearing. But vsync adds some input latency, so offer it as a player option rather than forcing it. For modern setups, support variable refresh rate displays, which eliminate tearing without the latency cost of traditional vsync.

Quick answer: Screen tearing is a horizontal tear line where the display shows parts of two different frames at once, caused by the game swapping the display buffer mid-refresh (frame presentation not synchronized with the display's refresh cycle). Fix it by enabling vsync (which syncs buffer swaps to the refresh, eliminating tearing) or supporting variable refresh rate displays, while being mindful that vsync adds some input latency, so offer it as a player option.

Screen tearing, that distracting horizontal line where the image looks split and misaligned during motion, is a frame-presentation timing problem. It's well-understood and the primary fix (vsync) is standard, but it comes with a tradeoff (latency), so the real answer is giving players appropriate options. Understanding why tearing happens clarifies the fix.

Why Screen Tearing Happens

The display refreshes the screen at a fixed rate (e.g. 60Hz), reading the frame buffer top to bottom. If the game swaps to a new frame in the buffer while the display is partway through reading the old one, the display shows part of the old frame (above the swap point) and part of the new frame (below it), creating a visible tear line where they meet. Tearing occurs because the game's frame presentation (when it swaps buffers) isn't synchronized with the display's refresh cycle, so swaps happen mid-refresh.

Tearing is most visible during motion (the two frames differ more, making the misalignment obvious) and when the frame rate isn't aligned with the refresh rate. It's fundamentally about the timing of buffer swaps relative to the display refresh, which is exactly what synchronization addresses.

How to Diagnose It

Screen tearing is visually distinctive, a horizontal line during motion where the image is split/misaligned, often moving up or down the screen. It's reproducible by moving the camera/scene quickly with synchronization off. Check whether vsync (or another sync method) is enabled, tearing with no sync is expected, since without synchronizing buffer swaps to the refresh, swaps happen mid-refresh and tear.

It's primarily a configuration issue (sync settings) rather than a hardware-specific bug, though variable-refresh-rate displays change the picture. Players may report tearing or a 'line' during motion. The fix is about presentation synchronization settings, which you control.

How to Fix It

Synchronize frame presentation with the display refresh. Enable vsync (vertical sync), which makes the game wait to swap buffers until the display finishes a refresh, so a new frame is only presented at the start of a refresh cycle, eliminating tearing. This is the standard fix. The tradeoff: vsync can add input latency (and can cause frame-rate stepping/judder if the game can't keep up), so it's not universally desirable, competitive players often prefer tearing over the latency. Therefore, offer vsync as a player option (on/off) rather than forcing it, letting players choose tear-free or low-latency.

For modern setups, support variable refresh rate (the display adjusts its refresh to the game's frame rate), which eliminates tearing without the latency cost of traditional vsync, the best of both where available. After implementing, verify vsync removes tearing (and that you offer the option), and that variable refresh rate is supported where applicable. The complete answer is giving players the synchronization options, vsync, off, and variable refresh rate support, so they can balance tearing against latency for their setup and preference.

Tearing is buffer swaps happening mid-refresh. Vsync fixes it by syncing swaps to the display, but it adds latency, so offer it as an option and support variable refresh rate where you can.