Nvidia G-Sync

G-Sync is a proprietary adaptive sync technology developed by Nvidia aimed primarily at eliminating screen tearing and the need for software alternatives such as Vsync.^[1] G-Sync eliminates screen tearing by allowing a video display's refresh rate to adapt to the frame rate of the outputting device (graphics card/integrated graphics) rather than the outputting device adapting to the display, which could traditionally be refreshed halfway through the process of a frame being output by the device, resulting in screen tearing, or two or more frames being shown at once.^[2] In order for a device to use G-Sync, it must contain a proprietary G-Sync module sold by Nvidia. AMD has released a similar technology for displays, called FreeSync, which has the same function as G-Sync yet is royalty-free.

Nvidia built a special collision avoidance feature to avoid the eventuality of a new frame being ready while a duplicate is being drawn on screen (something that could generate lag and/or stutter) in which case the module anticipates the refresh and waits for the next frame to be completed.^[3] Overdriving pixels also becomes tricky in a non-fixed refresh scenario, and solutions predicting when the next refresh is going to happen and accordingly adjusting the overdrive value must be implemented and tuned for each panel in order to avoid ghosting.^[4]