This might not be a bug... Because X11 fractional scaling is implemented using an extra-large screen buffer and copying it (scaled down) to the real framebuffer. Both of those facts make Xorg fractional scaling much slower than integer scaling. Wayland fractional scaling has no such performance problems but the Nvidia driver is not well supported with Wayland :(
I suggest your best options are either: * Don't use fractional scaling at all; or * Enable experimental Nvidia Wayland support: 1. In /etc/default/grub add the kernel parameter: nvidia- drm.modeset=1 2. Comment out the Nvidia rule that is disabling Wayland in /usr/lib/udev/rules.d/61-gdm.rules ** Changed in: mutter (Ubuntu) Status: New => Won't Fix -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1907189 Title: Apps become unresponsive and lag when multiple windows opened and fractional scaling enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1907189/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs