What is adaptive sync?
Screen tearing occurs when your GPU renders frames at a different rate than your monitor refreshes. A 144Hz monitor showing a 87fps game result in a visible horizontal split where two frames overlap.
Adaptive sync solves this by letting the monitor's refresh rate follow the GPU's output in real time. Instead of a fixed 144Hz, the display might be refreshing at 87Hz to match exactly one frame per cycle.
G-Sync (NVIDIA)
NVIDIA's G-Sync requires a proprietary hardware module inside the monitor. This module handles all the variable-refresh rate logic and also provides precise overdrive control, HDR handling, and ULMB (Ultra Low Motion Blur) backlight strobing.
G-Sync variants:
FreeSync (AMD)
FreeSync is based on the open VESA Adaptive-Sync standard built into DisplayPort and HDMI 2.1. No proprietary hardware required - manufacturers implement it in firmware. The result is lower cost and widespread availability.
FreeSync tiers:
NVIDIA + FreeSync
Modern NVIDIA GPUs (Pascal and later) support G-Sync Compatible, meaning they can use FreeSync monitors. The experience is not as perfectly tuned as native G-Sync, but for most people it is indistinguishable.
Does adaptive sync matter?
If your GPU consistently renders above your monitor's refresh rate, you can use VSync without feeling input lag (since frames are never waiting). Adaptive sync matters most when your framerate fluctuates - which is the common case in demanding open-world games.
Verdict: For most gamers, a FreeSync Premium or G-Sync Compatible monitor is plenty. Full G-Sync is only worth the premium if you need the wider sync range or ULMB strobing.