This bug should now track the release status of: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4015 and https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4027
** Tags added: multimonitor -- 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/2105500 Title: Low FPS on wayland when running dual monitors on laptop with Nvidia GPU and iGPU Status in mutter package in Ubuntu: Fix Released Status in mutter source package in Noble: Triaged Status in mutter source package in Oracular: Triaged Status in mutter source package in Plucky: Fix Released Bug description: I have a Lenovo P16 Gen 2 laptop with both an NVIDIA GPU and an Intel iGPU. I must say, Wayland sessions work phenomenally well—everything feels incredibly smooth compared to my old Ubuntu 20.04 X11 sessions. However, this changes the moment I plug in an external display. (For context: my machine has two USB-C ports with DisplayPort support and one HDMI port—all three are wired to the NVIDIA GPU, not the iGPU.) When I connect an external display, it is detected immediately, but the frame rate drops significantly on both the built-in and the external screens. I’ve tested different configurations: duplicating displays, extending them, or using the external display only. In all cases, the frame rate remains degraded. The only case where frame rates return to normal is when I select only the built-in display. What I’ve tried: I’ve tested multiple GPU drivers, all in Wayland sessions. Based on performance, this is the ranking I observed: nvidia-driver-570 (with GSP firmware) < nvidia-driver-570 (without GSP firmware, i.e., with Nvreg_EnableGpuFirmware=0) < nvidia-driver-570-open < nouveau The nvidia-driver-570-open performs noticeably better than the proprietary version, but it still doesn’t match the performance of the system without an external display connected. Interestingly, when I open an X11 session with both displays connected, there is no noticeable performance drop compared to using the built-in display alone. So clearly, the FPS drop is specific to Wayland. Also worth noting: once I remove the external display, the Wayland session becomes smooth again on the built-in screen. This reinforces that the issue occurs only when an external display is actively in use. An interesting workaround: In all scenarios where frame rates drop, enabling screen capture (e.g., via OBS) causes the system to suddenly run at high FPS again—everything becomes smooth. As soon as screen capture is disabled, the frame rate drops once more. I discovered this workaround from [1]. Additional context and references: Googling around, I’ve found that this seems to be a relatively common issue (and likely not limited to Ubuntu 24.04.2). In particular, [3] identifies what appears to be the same issue—related to mutter—and proposes a “fix” that reportedly restores normal FPS behavior. I’m including below a list of relevant discussions and bug reports. Please note [3] in particular, which may contain a direct fix for this problem. Definitely related: [1] https://forums.developer.nvidia.com/t/frequent-lags-and-loss-of-smoothness-in-kde-plasma-with-dual-monitors-on-nvidia-3070-ti-wayland-x11/311888 [2] https://discourse.gnome.org/t/wayland-external-monitor-refresh-rate-issue-nvidia-gpu/20652 [3] https://gitlab.gnome.org/GNOME/mutter/-/issues/3461 [4] https://askubuntu.com/questions/1534213/wayland-on-4k-monitor-set-at-60-hz-feels-like-30-hz Possibly related: [5] https://www.reddit.com/r/wayland/comments/168q67n/poor_performance_and_lags_on_nvidia_laptop_with/ [6] https://gitlab.gnome.org/GNOME/mutter/-/issues/3544 ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: gnome-shell 46.0-0ubuntu6~24.04.8 ProcVersionSignature: Ubuntu 6.11.0-21.21~24.04.1-generic 6.11.11 Uname: Linux 6.11.0-21-generic x86_64 NonfreeKernelModules: socwatch2_16 vtsspp sep5 socperf3 pax ApportVersion: 2.28.1-0ubuntu3.5 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Mon Mar 31 12:29:48 2025 DisplayManager: gdm3 InstallationDate: Installed on 2025-03-20 (11 days ago) InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215) RelatedPackageVersions: mutter-common 46.2-1ubuntu0.24.04.6 SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2105500/+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
