Ubuntu 22.04 is the first release of Ubuntu that works well on the Raspberry Pi 4 without any lag or stutter. Most of the credit for this goes to the work done on the Mesa drivers over the last year by Igalia. The 2D graphics support and Vulkan 3D support for the Pi 4 are currently in great shape and continue to pick up improvements.
This article provides a few tips to improve the performance further.
Update: PiMix has been discontinued since October 2021 due to very few downloads, and the release of Ubuntu 22.04. The Ubuntu Gnome desktop on 22.04 runs well on Pi 4 without any lag, and it is no longer necessary to use a lightweight desktop like Xfce.
Please try the official Ubuntu desktop if you need an alternative.
PiMix 21.10 is now available based on Ubuntu 21.10 (Impish Indri).
PiMix is a remixed version of 64-bit Ubuntu for the Raspberry Pi 4 that is optimized for desktop use.
FlashIt is an app for managing USB sticks and SD cards. It can flash ISO/IMG files to USB sticks, create compressed backup images, format the card for storage, clone SD cards, mount/umount disk images, etc.
