It is observed NVIDIA G-SYNC is also useful for low-latency fixed refresh rate applications as well: It accelerates frame delivery from GPU to monitor: Frames are delivered from GPU to monitor in 1/144sec instead of 1/60sec when running at 60Hz!
Low-lag fixed-refresh-rate G-SYNC has uses for emulators and other applications that requires a fixed refresh rate (e.g. 60Hz) with an ultra-low input lag.