How it works
G-SYNC and FreeSync describe families of variable-refresh features. Instead of updating only on a fixed schedule, a compatible screen can align refresh timing with completed frames within a supported range. This can reduce the visible split between different frames known as tearing. It does not create extra rendering performance or automatically fix long pauses caused by loading, insufficient memory or another bottleneck.
Compatibility involves the graphics device, driver, display input, cable and monitor settings. A monitor may support the feature on one connection but not another, and advertised certification tiers can include different requirements. Behaviour outside the variable-refresh range depends on the supported implementation and selected settings. The presence of a logo is therefore a starting point for checking compatibility, not a promise that every connection and game will behave identically.
Practical checks
Consult the monitor and graphics-device documentation, use a supported input and confirm that variable refresh is enabled in the relevant controls. Compare the same game scene before and after changing the setting. Distinguish tearing from uneven frame times and from network lag. If the display flickers or loses its connection, restore the working configuration and investigate supported ranges, cable quality and drivers rather than repeatedly changing unrelated graphics options.