What Is VSync and Input Lag? When to Turn VSync Off

Screen Tearing Recap

When your GPU renders frames faster than your monitor can display them, the monitor scans out part of one frame and part of the next simultaneously — creating a horizontal tear. VSync prevents this by capping the GPU's output to the monitor's refresh rate.

The Problem with VSync

Traditional VSync uses a double-buffer strategy: the GPU finishes a frame and waits for the monitor to finish its current refresh cycle before displaying it. This waiting introduces input lag — the delay between pressing a key/moving your mouse and seeing the result on screen. At 60 Hz with VSync on, input lag adds up to 16.7 ms per frame. At 144 Hz, the impact is smaller (6.9 ms) but still noticeable in competitive play.

Triple Buffering

Triple buffering reduces VSync's input lag by allowing the GPU to render into a third buffer while waiting. This improves frame pacing but increases VRAM usage and still adds some latency compared to no VSync.

Fast Sync and Enhanced Sync

NVIDIA Fast Sync and AMD Enhanced Sync are hybrid approaches: the GPU renders at full uncapped speed, but only the most recently completed frame gets displayed. Tearing is minimized while input lag is similar to no VSync. These work best when your frame rate is significantly higher than your monitor's refresh rate.

When to Use What

• Competitive shooters (CS2, Valorant, Apex Legends): Disable VSync, enable adaptive sync (G-Sync/FreeSync), cap FPS just below monitor max
• Story/RPG games: VSync or adaptive sync is fine; tearing is more distracting in cinematic games
• If you have adaptive sync: Use it instead of VSync — best of both worlds

MrGameFix optimization scripts set game-appropriate VSync and frame cap settings per title.