Question Main monitor resolution breaks when going 1440p 240hz HDR

[siaan312]

My monitor is a samsung G7.
I recently got a rtx 3090 and replaced my old gtx 1080 with it, and now when I open some games, the resolution of my screen breaks.
it seems like my screen streches to 32:9, and I'm only shown the left 16:9.
Meaning I can see the left side of the screen, while the right side is not there, but I can see top to bottom.
The resolution also seems really low, even though both in display settings and nvidia control panel it says 1440x2560 240hz.

I first noticed it in call of duty, where the moment I opened the game the entire screen resolution broke like this.
turning the resolution to 1080p, or turning the refresh rate to 144hz both fixed it.
I also now realized that even in the desktop, without any games running, turning HDR does the same issue.
This was not an issue with the GTX 1080.
I have a few theories, but I'd like suggestions and potential fixes.

Maybe DSC is not working, my old GTX 1080 did not have DSC, and I have chroma subsampling on.
My displayport cable does not support DSC/1.4 in general.
Something I don't know with the monitor.

 

[siaan312]

My monitor is a samsung G7.
I recently got a rtx 3090 and replaced my old gtx 1080 with it, and now when I open some games, the resolution of my screen breaks.
it seems like my screen streches to 32:9, and I'm only shown the left 16:9.
Meaning I can see the left side of the screen, while the right side is not there, but I can see top to bottom.
The resolution also seems really low, even though both in display settings and nvidia control panel it says 1440x2560 240hz.

I first noticed it in call of duty, where the moment I opened the game the entire screen resolution broke like this.
turning the resolution to 1080p, or turning the refresh rate to 144hz both fixed it.
I also now realized that even in the desktop, without any games running, turning HDR does the same issue.
This was not an issue with the GTX 1080.
I have a few theories, but I'd like suggestions and potential fixes.

Maybe DSC is not working, my old GTX 1080 did not have DSC, and I have chroma subsampling on.
My displayport cable does not support DSC/1.4 in general.
Something I don't know with the monitor.

Update:
It seems turning output color depth to 10bpc in the nvidia control panel is what causes this.

How can I fix it so 10bpc does work, or maybe it shouldn't on my monitor or gpu?
Does it even matter?