Think I found it. The new version of triple buffering in mutter 44.0 is too aggressive at scaling back to double buffering. So that's why 22.04 and 22.10 felt faster on Pi than 23.04 does right now.
The workaround is to add this to /etc/environment: MUTTER_DEBUG_TRIPLE_BUFFERING=always ** Tags added: triple-buffering ** Tags added: regression-release ** Changed in: mutter (Ubuntu) Assignee: (unassigned) => Daniel van Vugt (vanvugt) ** No longer affects: linux-raspi (Ubuntu) ** Changed in: mutter (Ubuntu) Importance: Undecided => Medium ** Changed in: mutter (Ubuntu) Status: New => Triaged -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2017097 Title: [raspi] GNOME Shell runs at 30 FPS unless the CPU is being stressed Status in mutter package in Ubuntu: Triaged Bug description: On a Raspberry Pi 400, GNOME Shell runs at 30 FPS unless the CPU is being stressed in which case it becomes a smooth 60 FPS. Seems like a frequency scaling issue. ProblemType: Bug DistroRelease: Ubuntu 23.04 Package: mutter (not installed) ProcVersionSignature: Ubuntu 6.2.0-1004.5-raspi 6.2.6 Uname: Linux 6.2.0-1004-raspi aarch64 ApportVersion: 2.26.1-0ubuntu2 Architecture: arm64 CasperMD5CheckResult: unknown Date: Thu Apr 20 15:13:51 2023 ImageMediaBuild: 20230417 SourcePackage: mutter UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2017097/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp