What is vsync

What is VSync?

VSync, short for vertical synchronization, is a display technology that synchronizes a game's frame rate output with your monitor's refresh rate. The primary purpose of VSync is to eliminate screen tearing—a visual artifact that occurs when your GPU renders frames faster than your monitor can display them.

The Problem VSync Solves

Screen tearing happens when the GPU completes a new frame while the monitor is in the middle of displaying the previous frame. This creates a visible horizontal line or tear across the screen, dividing it between two different frames. In fast-paced games, this can be distracting and impact the gaming experience. VSync addresses this by limiting the frame rate to match the monitor's refresh rate, ensuring frames align perfectly with display refreshes.

How VSync Works

When VSync is enabled, the GPU waits for the monitor to complete its refresh cycle before sending the next frame. On a 60Hz monitor, VSync limits the frame rate to 60fps. On a 144Hz monitor, the limit is 144fps. This synchronization prevents frames from being sent at the wrong time, eliminating the tearing effect. The GPU uses a signal called the vertical blanking interval to determine when the monitor is ready for a new frame.

Advantages and Disadvantages

VSync provides the benefit of eliminating screen tearing, creating a cleaner visual presentation. However, it comes with trade-offs. VSync can introduce input lag—the delay between your controller input and the on-screen response—because the GPU may need to buffer frames while waiting for the monitor. Additionally, if your graphics card cannot maintain the target frame rate, VSync causes the frame rate to drop to half the refresh rate, creating noticeable stuttering (e.g., from 60fps to 30fps on a 60Hz monitor).

VSync vs Other Technologies

Modern alternatives to VSync have emerged to address its limitations. G-Sync and FreeSync (both VRR technologies) dynamically adjust the monitor's refresh rate instead of locking the game's frame rate, providing tear-free gaming without input lag or stuttering issues. Many gamers now prefer VRR over traditional VSync for a superior gaming experience.

When to Use VSync

VSync is useful when your GPU can consistently maintain the target frame rate without drops. For competitive gaming where input lag matters, turning off VSync and using a high refresh rate monitor may be preferable. For single-player games or situations where frame rate stability is more important than input responsiveness, VSync can be beneficial.