Display Enlightment by NCX

The LG scales 1280x720 and 1920x1080 without issue, but as expected, native 1080p monitors look better than the LG when it is set to 1080p.  The Xbox 360 must have its YCbCR709's setting selected to prevent the image from being washed out since the other settings send a 16-235 signal.

Spoiler (hover to show)

Use the following Image Settings

System Settings> Console Settings> Display> HDTV Settings>Select 1080p

Enable Display Discovery in the System Settings>Console Settings>Display Settings tab or

System Settings> Console Settings> Display> Reference Levels: Standard

System Settings> Console Settings> Display> Color Space>YCbCr709

The Acer automatically reads both the Limited (16-235) and Full (PC RGB 0-255) signals sent out by the Xbox One and Xbox One X, so no settings need to be changed.  Free-Sync must be manually activated in both the LG 27UL550's menu and by whichever Free-Sync compatible device the monitor is connected to, those being a compatible graphics card or Xbox One X.  To activate the 27UL550's FreeSync setting go into the Picture Menu, select the Game Adjust sub menu and set FreeSync to On.


The Allow variable refresh rate setting must be selected in the Xbox One S and X's Display & sound Advanced video modes menu.  Here's how to access this setting:

1.) Open the Settings app on Xbox One.
2.) Navigating to the Display & sound tab.
3.) Select the Video output tile.
4.) Select Video modes.
5.) Enable the Variable Refresh Rates checkbox.

Source=Xbox One FreeSync and Variable Refresh Rates: Everything you need to know by Matt Brown