[SOLVED] Why does my display behave differently on essentially the same resolution?

[p91og]

Sometimes my monitors OSD says its outputting at 1080p @60hz, when it is everything feels like its running smoothly, yet sometimes it then says outputting at 1920x1080 @60hz and the game seems to become sluggish and have a significant amount of input lag. I know they're essentially the same resolution but why do they feel different. I'm on an Xbox One X which only has the option for 1080p not 1920x1080 even though its the same thing, so I'm not sure if my monitor is defective? Its like 3 or 4 years old. btw, I'm not sure if these forums are strictly for PC so, sorry if they are.

 

[Glenwing]

"1080p" likely refers specifically to the CTA-861 format VIC 16, which specifies the exact transmission timings (1920×1080 / 2200×1125, 60.000 Hz, 148.500 MHz), which is the standardized format used by TVs. "1920×1080" refers to any format with 1920×1080 active pixels.

I don't know why they would feel different though.