0

I have a Lenovo Gaming i3 with a GTX 1650 and am running Ubuntu 20.04 latest. The laptop's screen is 1080p 120Hz and I connect an external 1080p 60Hz monitor. When the monitor is connected my laptop's 120Hz screen drops to about 60Hz and it experiences some vertical tearing. xrandr reports the laptop screen as 120Hz the entire time, even though it's clearly not.

How can I run my laptop's screen at 120Hz and the external monitor at 60Hz in the same time?

Changing the PRIME profile in Nvidia X Server settings to Preformace Mode only makes the problem worse. When I do that, I get a lot of vertical tearing and it does nothing to the refresh rates. In fact, changing to Preformance Mode makes the screen tear even without an external monitor. Changing to On Demand makes the tearing stop, but that's because it's using the AMDGPU from the processor and not Nvidia. On Demand does not fix the refresh rate issue.

I've also tried toggling vsync, but it made no difference to refresh rates or tearing. I've tried downgrading nvidia-driver, but it also made no difference. Enabling Force composition pipeline also did nothing. Reinstalled the driver multiple times at this point. Still nothing. The problem happens on all monitors that I've tested. And I know it's not a hardware limitation because Windows 10 on the same laptop works out of the box with both monitors at the correct refresh rate and without any tearing.

This is my xrandr with both displays:

$ xrandr
Screen 0: minimum 320 x 200, current 3840 x 1080, maximum 16384 x 16384
eDP connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1920x1080    120.21*+
   1680x1050    120.21  
   1280x1024    120.21  
   1440x900     120.21  
   1280x800     120.21  
   1280x720     120.21  
   1024x768     120.21  
   800x600      120.21  
   640x480      120.21  
HDMI-1-0 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080     60.00*+  59.94    50.00  
   1680x1050     59.95  
   1440x900      59.89  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      60.00    59.94    50.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    72.81    59.94    59.93  

1 Answer 1

0

I solved this problem and it is the only way:

steps (google each step please):

  1. Use Ubuntu 21.04 (not working in ubuntu 21.10)
  2. Install Nvidia driver 470 (maybe higher version)
  3. blacklist nouveau
2
  • I assume you meant to post a link? There is no link in your post
    – Ciprum
    Mar 27, 2022 at 11:09
  • @Ciprum can you google the step? it would be a really long answer to write the detail.
    – Jake
    Apr 1, 2022 at 10:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.