What is V-Sync? Fix screen tearing without adding lag

The problem V-Sync solves

Your monitor redraws the picture a fixed number of times per second. A 60 Hz screen does it 60 times, a 144 Hz screen 144 times. Your graphics card, on the other hand, finishes frames whenever it is ready, and that speed changes from second to second.

When the card hands over a new frame while the monitor is halfway through drawing the old one, the screen shows the top part of one frame and the bottom part of the next. The seam between them is called screen tearing. It looks like a horizontal crack that jumps around during fast sideways movement.

What V-Sync does

V-Sync (vertical synchronisation) makes the game wait. A new frame is only swapped in at the exact moment the monitor starts a fresh redraw. No swap mid-draw means no tear.

The price is waiting. If a frame misses the deadline, it sits until the next refresh. With classic V-Sync on a 60 Hz screen, a card that can only manage 50 fps may be pushed down to 30 fps, because every frame just misses the 1/60 second deadline and waits for the next one. Many modern drivers and games soften this with extra buffering, but you still get uneven frame times and extra delay between pressing a button and seeing the result.

Try it yourself

Pick a refresh rate, set how fast your graphics card renders, and switch V-Sync on or off. The white bar sweeps across the screen like the monitor redraw. Watch the seam.

Two things to notice. With V-Sync off the torn count climbs whenever your fps and the refresh rate do not line up, and a higher fps does not remove tearing, it only changes where the seam lands. With V-Sync on the tears disappear, but the average wait before a frame is shown goes up, and a slow card loses frames it could otherwise have displayed.

Variable refresh rate: the better fix

Variable refresh rate (VRR) flips the problem around. Instead of making the game wait for the monitor, the monitor waits for the game. It starts each redraw when a frame is ready, within the range the screen supports. NVIDIA calls its version G-Sync, AMD calls its FreeSync, and the open standard behind much of it is HDMI and DisplayPort adaptive sync. You need a monitor and a graphics card that both support it, and it must be switched on in the monitor menu and the graphics driver.

VRR only works inside the monitor's range. If your fps goes above the maximum refresh rate, tearing can return. That is why many guides suggest turning on V-Sync in the driver alongside VRR, and capping the frame rate a few fps below the maximum refresh rate. The V-Sync setting then only acts as a safety net near the top of the range.

Which setting should you use?

What to remember

Tearing is a timing mismatch, not a sign of a broken screen. V-Sync fixes it by making frames wait, which costs a little responsiveness. VRR fixes it by making the screen wait, which is why it is usually the nicer answer if your monitor has it. Consoles handle most of this for you, but many TVs and monitors still have a VRR switch worth checking.