It has to do with aligning stream and your.

Adaptive vsync. When the framerate is under the monitors refresh rate (ie 45fps. A most common question that what is adaptive sync? It eliminates tearing and stuttering caused by mismatches.

Which is there beside vsync off and on as additional option. At low frame rates, it's disabled to minimise. Op is actually talking about adaptive vsync option in windows gfn app.

To give you an idea of how it's done, here’s how to enable vsync through nvidia’s control panel on your pc. Adaptive sync is a vesa standard. At high framerates, vsync is enabled to eliminate tearing.

When you can hit the same framerate (or higher) as your monitors refresh (ie 60fps and 60hz), then vsync is on. Yet, their display rate remains smaller. In many cases, vsync has huge potential to refresh the frame rate to more than 60 per second.

Hit the start button and type nvidia control. Outside of gaming, adaptive sync can also be used to enable seamless video playback at various framerates, whether from 23.98 to 60 fps. Fast sync is a more advanced form of adaptive vsync from nvidia that enables vsync when necessary and adds in automatic triple buffering to pick the best frame.

Fast sync basically renders as many frames as the gpu possibly can, and drops the ones that aren't required. Fastsync is nvidia’s version of adaptivesync and an upgrade of its own adaptive vsync, which was considered a bit of a mess. Adaptive vsync is a smarter way to render frames using nvidia control panel software.