I bought a new Lenovo Legion 27" OLED 240hz monitor a few days ago and for some reason the highest refresh rate I can choose is 165hz. I have done some troubleshooting and asked a friend who also uses linux for help who sent me this troubleshoot from the arch wiki NVIDIA/Troubleshooting - ArchWiki but nothing has worked so far. I’m on KDE plasma desktop with wayland and my specs are AMD Ryzen 7 7800X3D and a Nvidia Geforce RTX 3060, I’m using a brand new display port cable that came with the monitor, t
Please take this as just my view, and as a tester Some users have noted that the 27Q-10 may have firmware or panel revisions that cap reporting at 165Hz despite marketing claims, so verify your specific model number (e.g., 67E1GAC1WW) against official specs.
Been fighting this for a friend as well, desipte any cables used.
DisplayPort 1.4 cable is the most common fix for reaching 240Hz. (But not for all) .
Something like this:
https://www.lenovo.com/us/en/p/accessories-and-software/cables-and-adapters/cables/4x91u92142
I’m keeping an eye on this thread. 
The model number for my monitor is 67E1GAC1EU, the monitors setting is set to DP 1.4 but I’m not sure if the cable that was included with it is 1.4. Thanks btw for the fast answer!
It may be worth it to purchase specifically a new DP 1.4 cable for that monitor. It seems quite possible that the included cable may not be up to that spec so would not be able to support the higher refresh rate.
Alright I’ll try and get a new one and see if that works!
I went and bought an 1.4 display port cable and still can’t get 240hz on the monitor
The 3060 is hardware capable of supporting 240Hz according the NVidia.
What does kscreen-doctor -o report?
Is a 240Hz mode reported buy the display?
Please post text as pre-formatted trxt not screen shots.
I cannot search the image…
It seems you do not have 240Hz capable monitor.
I do not see a mode of 5hat refresh rate in the kscreen-doctor output.
If the monitor is advertised as have 240Hz refresh you should first raise a support ticket with the manufacturer. If they do not get know how to get it working then ask for a refund as the produce does not do what it claims to be capable of.
Oh I’m sorry, do you mean like this?
Output: 1 DP-6 1b3c472d-8051-4dfb-baa2-a4c15eb6efef
enabled
connected
priority 2
DisplayPort
replication source:0
Modes: 1:2560x1440@59.95! 2:2560x1440@165.07* 3:2560x1440@143.97 4:2560x1440@120.00 5:1920x1080@1
65.00 6:1920x1080@74.91 7:1920x1080@60.00 8:1920x1080@59.94 9:1920x1080@50.00 10:1600x900@74.89 11:1600x
900@60.00 12:1280x1024@75.03 13:1280x1024@60.02 14:1440x900@74.98 15:1440x900@59.89 16:1280x800@59.81 17
:1280x720@59.94 18:1280x720@50.00 19:1024x768@75.03 20:1024x768@70.07 21:1024x768@60.00 22:800x600@75.00
23:800x600@72.19 24:800x600@60.32 25:720x576@50.00 26:720x480@59.94 27:640x480@75.00 28:640x480@72.81 2
9:640x480@59.94 30:640x480@59.93
Custom modes: None
Geometry: 1920,0 2560x1440
Scale: 1
Rotation: 1
Overscan: 0
Vrr: Never
RgbRange: unknown
HDR: disabled
Wide Color Gamut: disabled
ICC profile: none
Color profile source: EDID
Color power preference: prefer accuracy
Brightness control: supported, set to 100% and dimming to 100%
DDC/CI: disallowed
Color resolution: unknown
Allow EDR: unsupported
Sharpness control: unsupported
Automatic brightness: unsupported
Auto Rotate Policy: incapable
Adaptive backlight modulation: unsupported
Hope this is what you meant, if not then tell me how and I’ll try again 
The monitor is advertised as 240hz and the 1.4 display port cable I bought says it is capable of 240hz at 2560x1440
Alright I have solved the problem, I feel pretty stupid but it was a setting on the monitor that seem to have been off as standard. I turned DSC on, which I had no idea about what it was till now, and now it can run on 240hz. Super big thanks to everyone who took the time to respond to this thread!
Not quite. That is plain text posted but not preformatted.
For preformatted text, paste the text as you did then highlight it and click the </> button on the toolbar, or you can enter ``` on the line preceding the text and again on the line following the text for the same results.
The result when properly preformatted should look exactly like it did on your screen.