Nvidia GTX 1650 not detected in Ubuntu 18.04.3

Solution 1:

From the poster's comment to a detailed fix;

Do not add graphics drivers ppa and if you did it, remove everything including the ppa.

Open up the Additional Drivers from menu and select the proprietary tested driver and reboot.

Then create the directory and copy the file in it by following commands:

    sudo mkdir /etc/X11/xorg.conf.d
    sudo cp /usr/share/X11/xorg.conf.d/10-nvidia.conf /etc/X11/xorg.conf.d

Then add Option "PrimaryGPU" "Yes" to the OutputClass of the following file

sudo vim /etc/X11/xorg.conf.d/10-nvidia.conf

It should look like this in the end:

Section "OutputClass"
    Option "PrimaryGPU" "Yes"    
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "AllowEmptyInitialConfiguration"
    ModulePath "/usr/lib/x86_64-linux-gnu/nvidia/xorg"
EndSection

Then reboot. After rebooting, try nvidia-smi command to see if it works.

I got gtx1660ti working with this soluiton well.