It's possible that your Xbox needs to be set to RGB Limited instead to RGB Full, OR your monitor needs to be configured to Full/PC RGB range for the HDMI port(s). If your monitor is set to full RGB but your Xbox is limited, then images will appear slightly brighter/less contrast-y then it would on your PC which has full RGB output.
In other words the RGB setting on your Xbox needs to match whatever your monitor is set to (some monitors don't have a setting, so they're stuck in either RGB limited or full.)
edit: The same applies for TVs as well.
Edited by user Monday, September 19, 2016 8:40:18 PM(UTC)
| Reason: Not specified