I'm having similar problems in 1:91.10.0+build1-0ubuntu0.20.04.1 with Thunderbird's CPU usage well over 25 % and for long periods and additionally causing root process Xorg to consume 15 % CPU.
See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1772673 The workaround for me is: gfx.webrender.force-disabled = true ** Bug watch added: Mozilla Bugzilla #1772673 https://bugzilla.mozilla.org/show_bug.cgi?id=1772673 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1959747 Title: [upstream] Very high CPU and slow responsiveness in Thunderbird 91 To manage notifications about this bug go to: https://bugs.launchpad.net/thunderbird/+bug/1959747/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
