Question 165hz monitor stuck on 60hz

[Clarkender]

So i've been using this CMI-GM32-FQ 2K 2560x1440@165hz gaming monitor for maybe a year now, and i've ran it with no issues ever since. but upon booting up my pc for the first time in a couple days, the boot screen was stretch-res, and it appears i'm capped at 60hz. windows advanced display settings, highest hz is 60. nvidia control panel, highest is 60hz for 2560x1440 (native), and i am not using any ultra hd resolutions. i've tried using CRU and nvidia custom resolutions to force 165hz on 2560x1440, but it makes the screen real buggy, screen goes off resolution and aspect, it's still 60hz, and the weirdest issue being that the screen goes to a bright green buggy display. so my monitor currently can NOT run 165hz whatsoever...

my gpu is the GeForce RTX 3060, and an update came out just today so i updated it to see if it would fix the issue early upon booting up, but it didnt help. i even reinstalled the new driver update.
the monitor is connected to my gpu (not motherboard) by dp cable, and yes it's the one that came with the monitor.
all drivers are up to date.
the only other cable i have is an old bad hdmi one, which i know for a fact isn't as good as the dp cable im currently using.
i've tried plugging my monitor into the other gpu dp port, nothing changes.
V-sync and image scaling in nvidia control panel are off. "preferred refresh rate" is on highest available.
scaling mode is aspect ratio, and scaling is performed on display.

i've been using this monitor and gpu for over a year and both and worked just fine ever since. this is very sudden.
i haven't opened any games upon discovering this issue, and have been looking at countless forums, which have all dissapointed in relation to my issue.
also ive checked my monitor settings, theres no option to change resolution or refresh rate.

 

[thestryker]

Try the HDMI cable you have just to see if booting portion is better or not and then see what appears in windows for available resolution/refresh. It's unlikely to be software related if the display is acting oddly before you get into windows.

 

[Clarkender]

Try the HDMI cable you have just to see if booting portion is better or not and then see what appears in windows for available resolution/refresh. It's unlikely to be software related if the display is acting oddly before you get into windows.

Alright so i connected the main monitor via the hdmi cable.
my options for refresh rate went from just 60 to 60, 120 and 144. i can set it to 120 just fine, but putting it on 144 causes the screen to go black a few seconds after applying.
also, i restarted the pc bc of it, and it booted up with the normal resolution instead of stretch-res.
i quickly changed it back to 120 upon booting so it wouldnt go black again.
the dp cable isnt damaged and ive been running 165 just fine for ages.
i can attach images or videos if you require them for further investigation

edit1: i set my gpu fan speeds to higher and i seem to be running 144 just fine now. however the gpu wasnt hot nor even warm so thats a bit weird.

edit2: plugged the hdmi cable from the monitor to the other gpu hdmi port and restarted to see if itd change anything. screen kept flashing black upon loading up the desktop and had to wait for the half second flashes to navigate to the control panel to change it back to 120 lol. im gonna restart on 144 but keep it in the same port to see if it is the port that was causing the flashing.

edit3: booted up fine, not flashing black. however there are a few noticable flashing green pixels on the screen. im starting to think this is all because i cleaned the monitor. (with just a cloth and soapy water. also theres no opening other than the ports which i tried not to go near)

as im typing this 'edit3' the screen has gone back to flashing black every few seconds. i changed it back to 120 and all the green pixels are gone. would you like me to attach the video i took of the green pixels?
also talking about the cleaning, i did it the day before first booting up my pc for the first time in a few days because my power was out.

edit4: i showed my friend everything ive said abt this issue and he said the same happened to him. he could run 165hz just fine then suddenly it could only run 120, then 75. but hadnt cleaned it recently prior to when it happened. he had cleaned it a while before it happened to him/

 

[thestryker]

Well if the HDMI cable works (more correctly at least) that means your issue is DP related. You mentioned trying multiple ports on the video card and HDMI works so I doubt it's the video card which means monitor or cable. I'd suggest buying a new DP 2.0 (or 1.4a if the cables are expensive where you are) cable just to try that out first in case there's some sort of connector or internal cable issue. If the cable doesn't resolve things I'd lean towards monitor and unless you have another machine (or maybe integrated graphics) you could test with RMA the monitor assuming it's still under warranty.

A lower quality HDMI cable could be causing the problems when you go to 144hz vs 120hz.

 

[Clarkender]

ill check if its under warranty.
what does test with RMA mean though?

 

[thestryker]

I mean test it with another system or integrated graphics. RMA the monitor if you test and it doesn't work or if you don't have anything else to test it with.

 

[Clarkender]

I mean test it with another system or integrated graphics. RMA the monitor if you test and it doesn't work or if you don't have anything else to test it with.

alright ill try that.

irrelevant but i just unplugged the monitors power and replugged it and restarted the pc to see if itd do anything, and now theres red pixels on the 120hz, so i went back down to 60.

 

[thestryker]

Hopefully it's just the low quality HDMI cable and not the monitor. With any luck a new DP cable will fix it as that'd be a lot simpler than a monitor replacement.

 

[Clarkender]

Hopefully it's just the low quality HDMI cable and not the monitor. With any luck a new DP cable will fix it as that'd be a lot simpler than a monitor replacement.

so i plugged the monitor into the motherboard (integrated graphics) and its just not detected. my other monitor isnt detected when plugged into the mb either so i cant give a clear answer on that part.

 

[thestryker]

so i plugged the monitor into the motherboard (integrated graphics) and its just not detected. my other monitor isnt detected when plugged into the mb either so i cant give a clear answer on that part.

You didn't mention what CPU you have so maybe it's one without integrated graphics? If it does have it then perhaps it's disabled in the BIOS.

 

[Clarkender]

i used to be able to plug my monitor/s into it so idk why it doesnt work now. ill check if its in bios.

after plugging the hdmi from the mb back to the gpu, i can run 120 without the red pixels?
its all confusing. events occur randomly. impossible to make out solutions.
forgot to say, i have an intel core i7--7700