Brief coverage below of installing Pop!_OS 22.04 LTS on a Mac Pro 5,1 from early 2009; or, more correctly, a Mac Pro 4,1 which has had a firmware upgrade applied such that it now reports as a 5,1.

Installation

Installation was a breeze with the usual steps:

• Add in a fresh SSD¹
• Download image from PopOS website
• Write to USB with balenaEtcher
• Power off and remove original drive with MacOS on it
• Boot from USB by pressing and holding alt on boot until you get the option (UEFI boot or similar)
• Install Pop!_OS onto new drive
• Power off, remove USB stick, put original drive with MacOS on it back in
• Boot from new drive by pressing and holding alt on boot until you get the option

Small issues to sort out

Sleep/suspend

• Sleep/suspend does not seem to work, as a result I turned this off
  • Settings -> Power -> Automatic suspend: Off

Drivers for older Nvidia graphics cards

• For old Nvidia cards², you are likely to get a cheeky message like the below in the kernel ring buffer …

[   50.017989] nvidia-nvlink: Nvlink Core is being initialized, major device number 235
[   50.018002] NVRM: The NVIDIA GeForce 9500 GT GPU installed in this system is
               NVRM:  supported through the NVIDIA 340.xx Legacy drivers. Please
               NVRM:  visit http://www.nvidia.com/object/unix.html for more
               NVRM:  information.  The 535.86.05 NVIDIA driver will ignore
               NVRM:  this GPU.  Continuing probe...
[   50.020267] NVRM: No NVIDIA GPU found.

… the upshot of which being desktop rendering with no hardware acceleration.

Thankfully there is a PPA we can use to easily get hold of the 340 drivers:

sudo add-apt-repository ppa:kelebek333/nvidia-legacy
sudo apt update
sudo apt-get purge '*nvidia*'
sudo apt install nvidia-340-updates nvidia-340-updates-dev xorg-modulepath-fix

A quick reboot later and a run of nvidia-settings should then confirm everything is in order, and the display is commensurately snappier.

Shorter password

• If you want short password
  • https://askubuntu.com/questions/113682/how-to-change-disable-password-complexity-test-when-changing-password

References

• https://www.reddit.com/r/linux_gaming/comments/uidipv/how_to_install_nvidia_driver_340_on_ubuntu_2204/
• https://forums.macrumors.com/threads/what-is-the-maximum-possible-ram-in-a-mac-pro-5-1-different-sites-have-different-answers.2027681/
• https://thehouseofmoth.com/the-differences-between-the-41-and-51-mac-pro/