Comment 7 for bug 1528422

Similar issue here:

I was using kernel 5.4.0.42.46 with nvidia-drivers-440, installed 5.8.3, booted into the new kernel and the graphics were way worse. Software & Updates still has the radio button selected for nvidia,

see attached, this looked terrible stretched across a 3440*1440 screen.

but:

hwinfo --gfxcard
Driver Info #0:
    Driver Status: nvidiafb is not active
    Driver Activation Cmd: "modprobe nvidiafb"
  Driver Info #1:
    Driver Status: nouveau is not active
    Driver Activation Cmd: "modprobe nouveau"
  Config Status: cfg=new, avail=yes, need=no, active=unknown

Then, Selected nouveau driver, apply, hwinfo says both drivers still inactive, restarted, looks good (hi res), nvidia settings absent from start menu settings, nouveau radio button highlit in software & updates,

hwinfo --gfxcard
  Driver Info #0:
    Driver Status: nvidiafb is not active
    Driver Activation Cmd: "modprobe nvidiafb"
  Driver Info #1:
    Driver Status: nouveau is active
    Driver Activation Cmd: "modprobe nouveau"
  Config Status: cfg=new, avail=yes, need=no, active=unknown
  Attached to: #7 (PCI bridge)

So nouveau is being used, graphics problem fixed, nvidia definitely the culprit of the graphics issues which had been plaguing me for about a year. I'll file a bug with them, however part of what took me so long to diagnose this was that I thought the nouveau drivers were broken since I could only get 1024*768. I spent hours trying to fix that, to no avail. Turns out there was nothing wrong with them, they just weren't selected. I didn't know this because I didn't think to check, I just believed the radio button. Feasibly the selected item is highlit until changed in the GUI or backend by the user, but it doesn't do an internal check (hwinfo or otherwise) to confirm that the driver it thinks is selected, is selected?

Thanks