Nvidia vs Nouveau drivers

nvidia-driver-390 and nvidia-driver-430 are proprietary Nvidia graphics drivers either of which can be installed from the default Ubuntu 18.04 repositories. Nvidia 390 driver and Nvidia 430 driver are also marked as proprietary not open source drivers in my Ubuntu 18.04 Additional Drivers tab of Software & Updates. Nvidia 440 driver (nvidia-driver-440) comes from ppa:graphics-drivers/ppa which also has nvidia-driver-390, nvidia-driver-410, nvidia-driver-415, nvidia-driver-430 and nvidia-driver-435.

I don't have any Nvidia PPAs enabled in my software sources, so I assume that both Nvidia 390 driver and Nvidia 430 driver are identified as proprietary is the default in Ubuntu 18.04. In the case of nvidia-driver-430 this package is identified as Copied from ubuntu bionic in Primary Archive for Ubuntu in the PPA however it is also identified as open source in Additional Drivers while the default repository nvidia-driver-430 package is identified as proprietary in Additional Drivers. If both of these drivers were created from the same source, they both should be identified as proprietary drivers instead of one driver being identified as open source and the other driver identified as proprietary.

The recommended proprietary Nvidia graphics driver for your computer's graphics processor can be installed from the terminal with the following commands:

sudo ubuntu-drivers autoinstall  
sudo reboot    

When installing a proprietary graphics driver, it is not necessary to uninstall the built-in Nouveau open source graphics driver. The two graphics drivers can be installed alongside each other allowing the open source graphics driver to be used as a fallback alternative in case there is a problem using the proprietary graphics driver.

The ubuntu-drivers autoinstall command installs drivers that are appropriate for automatic installation including their dependencies, and the Nvidia driver will also be updated automatically when an update is available.

The only open source Nvidia driver is nouveau. It is included in Linux kernel.

All installable Nvidia drivers are proprietary no matter where they come from or how they are listed in applications.

The Software & Updates until the recent Ubuntu releases shows all packages coming from a PPA as open source.