Very off-topic and should probably be split to a different thread, but Nvidia's Adaptive V-Sync (force v-sync only above display refresh rate) and VESA Adaptive-Sync (variable refresh rate) are two distinctly different things.
Radeon Chill seems to do something similar to the former (among other things) on the AMD side while G-Sync is the Nvidia equivalent of the latter.
Radeon Chill seems to do something similar to the former (among other things) on the AMD side while G-Sync is the Nvidia equivalent of the latter.