https://www.theverge.com/2018/3/10/17105224/microsoft-xbox-one-amd-freesync-support

Microsoft is adding support for AMD’s FreeSync displays to its Xbox One X and Xbox One S consoles soon. The upcoming Xbox spring update already includes 1440p support on the Xbox One S and Xbox One X for monitors, but the addition of FreeSync will allow compatible displays to sync refresh rates with Microsoft’s consoles.

FreeSync, like Nvidia’s G-Sync, helps remove tearing or stuttering usually associated with gaming on monitors, as the technology syncs refresh rates to ensure games run smooth. FreeSync and G-Sync are widely used on PC gaming systems and monitors, so the addition of 1440p resolution and FreeSync will appeal to Xbox owners who also have a gaming display.