I have a 4k monitor and I wanted to use fractional scaling because, otherwise, everything looks so tiny.
When I enable fractional scaling to 150%, everything looks stretched horizontally, and I can only see the upper-left corner of the desktop.
What can I do so it looks correctly?
You have to enable NVIDIA (Performance Mode) in NVIDIA Settings (PRIME Profiles section) if you are using NVIDIA card. Of course, fractional scaling should be enabled too.
I've just migrated from 16.04 to 22.04 on an AMD FX 6 core and Nvidia GTX 750Ti, using Nvidia's driver. Fractional scaling in 16.04 Settings works fine on the same hardware. On my new 22.04 install though, trying to use 1.25 scaling makes the screen looked stretched with ragged dark shades through the view and I have to revert. It may be that Ubuntu has left it to Gnome Tweaks to implement fractional scaling because that works fine for me on 22.04
sudo apt install gnome-tweaks
The same problem looks here to have existed in 20.04
See here for a discussion of why 1.25 scaling is more computationally intensive.
Did you try turning off fractional scaling and just scaling it normally at 150%? I had the same issue and mine worked best at 200% without Fractional Scaling on when using a single monitor. It takes a bit of trial-and-error to get it right.
