Ubuntu 20.04 lag issues

Question

I am using DELL Latitude 5495 with AMD ryzen 5 pro . I accidently updated from 18.04 LTS to Ubuntu Focal Fossa 20.04 (development branch) instead of LTS.

I have been facing a lot of lag/freeze issues very frequently. Pixelation of graphics is noticed and Cursor and keys freezes for a few seconds mostly while using a browser/application. Seems to get better temporarily with reboots.

How can I resolve these issues or shift to the LTS version of 20.04/rolldown to 18.04 LTS to avoid them without losing data? (I am fairly new to linux)

It is similar to Random temporary screen lags since upgrade to 18.04

The results of sudo lspci | grep VGA && sudo lshw -c video | grep configuration && glxinfo | grep -i vendor are:

04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] (rev d1)
04:00.7 Non-VGA unclassified device: Advanced Micro Devices, Inc. [AMD] Raven/Raven2/Renoir Non-Sensor Fusion Hub KMDF driver
       configuration: driver=amdgpu latency=0
server glx vendor string: SGI
client glx vendor string: Mesa Project and SGI
    Vendor: X.Org (0x1002)
OpenGL vendor string: X.Org

edit 2: In my case, It wasn't an issue with the drivers or swap, I downgraded the linux kernel from 5.4.0.12 to 5.3.0.28... works like charm!

Solution 1

In my case, It wasn't an issue with the drivers or swap, I downgraded the Linux kernel from 5.4.0.28 to 5.3.0.28 by selecting advanced Ubuntu options in grub,booting into old kernel and removing the problematic kernel (here 5.4.0.28) by:

sudo apt-get purge linux-image-unsigned-5.4.0-28-generic

which gives error:

rmdir: failed to remove '/lib/modules/5.4.0-28-generic': Directory not empty.

manually remove the directory by:

sudo rm -rf /lib/modules/5.4.0-28-generic

Then update grub:

sudo update-grub2

... works like charm!

Solution 2

I know your problem has been solved. I too faced this problem after upgrading to Ubuntu 20.04 from 19.10 and I tried downgrading the kernel(to ```5.2.21``), updating nvidia drivers and changing swapiness but these didn't work.

In the end, I tried disabling running applications. I found that System Load Indicator was causing the lags.