nice name for an Emulator.
A g-sync for a c64 game sounds overkill.
G-Sync = will sync frames to video with GPU rendered frames = 50/60Hz will look butter smooth, as well as 54.70Hz for a MAME game... To achieve the same without G-Sync/Freesync you should have a video mode for EVERY single exact res (50, 49.97, 54.70Hz etc...). It is a tech incredibly useful for old emulator and their strange refresh rates.