Xbox One X won't output 1440p at 120hz

Xbox One X supports 1440P and 120Hz or 4K and
60Hz. By attaching HDMI 2.1 or 2K@120 via HDMI 2.0. The cable will output just 1440P@120Hz only, in the end, this is a monitor that most suitable for PCs. Check the Video Output settings and tweak it accordingly. Your monitor, unfortunately, doesn't support
ALLM or VRR.

Good luck!

My monitor is 1440p 144hz over HDMI 2.0, however I cannot get my Xbox One X to output at 1440p 120hz. If I override the display to HDMI, I am able to change the refresh rate to 120hz but it will automatically bump my resolution down to 1080p. If I turn
the resolution back up to 1440p it bumps it back down to 60hz. I've tried disabling freesync on my monitor but that doesn't help. Anyone have any ideas?

I figured it out, man! Me too, I was in your case, and I found the solution tonight after having "tinkered" with the options for a long time, guided by an article that made me understand the incompatibility of some options that we were tempted to
activate...

Basically, and follow to the letter what I'm about to tell you, okay?

1°) The first thing you have to do, and don't ask me the question, is to disable the 4K content in the console settings ;

2°) The second thing is not to activate the Freesync on your monitor, even the Freesync2 ;

3°) As for the third one, it's to switch your screen from 144 Hz to 120 Hz since you also have a gaming monitor.

4°) You just have to switch your resolution to 1440p, and your framerate to 120 fps, and that's the victory, man !

And just to get you up to speed, mate: the Freesync, if it's compatible with the console's "VRR", it's not compatible with the 120 Hz refresh, nor with the HDR; the mistake I was always making too... Otherwise, to compensate for the lack of HDR, if you have
access to the "Response Time" option in your monitor settings, activate it at the first or second level to gain in lighting quality and you will have a superb image! Also, the 120 fps is not compatible with the "VRR" and "Automatic Low Latency" modes, but
that's okay because the 120 fps is well held by the beast!

And so, I tested tonight this same config on Resident Evil 3 Remake, and let's drop it, it sends some pate! On that note, mate... enjoy the upcoming games with this magical 1440p/120fps combo !

PS: It's thanks to this article that I understood the beast, it's in French, because I'm French, but via DeepL, you can translate it to your language as I did to answer you : http://www.xboxygen.com/News/27030-FreeSync-et-VRR-Variable-Refresh-Rate-guide-et-infos-pour-tout-comprendre

Translated with www.DeepL.com/Translator (free version)

Hello, i have a xbox one x with the Samsung C27HG70QQ and if i put it in 1440 it changes the hz to 60. it only stays at 120 when its in 1080

what is faster game play hdr10 @60, 1440 @60 or 1080 @120?

also has anyone tried a display port to hdmi cable?

I would look into your monitor and call DELL not Microsoft. I also have a One X and have never had any problems, as soon as select 120hz it automatically drops me down from 4K to 1440p. You must be misunderstanding something about your monitor as there
must be a defect of some sort or your monitor does not support 1440p at 120hz.

For reference, before responding I booted on both my One X's. One is connected to a Samsung 4K QLED and I had no problem switching from 4k 60 to 1440p 120. My other X is connected via an LG 4K monitor and again when selecting 1440p OR 120hz it automatically
selects 1440p or 120hz without any issues.

Everything in my "chain" is compatable. My monitor is 1440p 144hz over Hdmi 2.0. I am using the cable that came with my Xbox One X which is 2.0. The problem seems to be with xbox.