The dynamic adjusting of a monitor's vertical refresh rate to the frame rate of the graphics card (GPU). Adaptive sync eliminates tearing, stuttering and judder and was developed for the video gaming industry. In order to be advertised as a gaming monitor today, it must support a variable and adjustable refresh rate. See tearing
, vertical sync
Adaptive sync was standardized by VESA and implemented in VESA's embedded DisplayPort (eDP) and DisplayPort 1.2a interfaces. AMD supports VESA Adaptive-Sync under the FreeSync brand.
G-Sync is an adaptive sync technology from NVIDIA that must reside in both the card and monitor. G-Sync is NVIDIA's proprietary technology and is a subset of VESA Adaptive-Sync. See GtG