What is VRR? G-Sync, FreeSync & Variable Refresh Explained
How variable refresh rate eliminates screen tearing without traditional VSync input lag.
1. Why Screen Tearing Happens
Without synchronization, the GPU transmits whatever frame buffer data is ready, even if the monitor is halfway through drawing the current frame. This splits the image horizontally, with the top half showing frame A and the bottom half showing frame B.
Traditional VSync fixes tearing by forcing the GPU to wait for the next vertical blanking interval, but introduces substantial input lag and severe stutter when frame rate drops below the monitor refresh rate.
2. The VRR Solution
Variable Refresh Rate (VESA Adaptive-Sync, NVIDIA G-SYNC, and AMD FreeSync) flips the relationship: the monitor refresh cycle waits dynamically until the GPU signals that a new frame is ready.
If your GPU renders at 83 FPS, your monitor refreshes at 83Hz. If it drops to 52 FPS, the monitor refreshes at 52Hz. The result is tear-free, perfectly paced motion with near-zero latency penalty.
Browser VRR Limitations: Browsers run inside the operating system window compositor. VRR is typically only engaged when an exclusive or borderless fullscreen window is focused and supported by your graphics driver.
Recommended Interactive Tests
Run these dedicated fullscreen tools to test your display against this guide's criteria:
Frequently Asked Questions
What is LFC (Low Framerate Compensation)?
When framerates drop below the monitor minimum VRR window (e.g. below 48Hz on a 48–144Hz monitor), LFC doubles or triples frame display (e.g. 40 FPS displayed at 80Hz) to keep VRR active without tearing.
Related Diagnostic Guides
Continue learning with complementary display inspection guides:
How to Test Monitor Refresh Rate & Frame Drops
Learn how browsers measure requestAnimationFrame intervals, how to verify whether your high-refresh monitor is truly running at 120Hz, 144Hz, or 240Hz, and how to fix frame skipping.
What is Monitor Ghosting & How to Eliminate It
A comprehensive guide to understanding monitor ghosting, pixel response times (GtG), overdrive tuning, and how to eliminate trailing on IPS, VA, and OLED panels.