It appears the nouveau kernel driver is crashing, which may well be the main problem here. And thanks for testing kernel 4.20 already.
As a workaround please try installing the official Nvidia driver. ** Package changed: xorg (Ubuntu) => xorg-server (Ubuntu) ** Package changed: xorg-server (Ubuntu) => linux (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1811159 Title: temporary freeze under opengl, not xrender, 18.10 & kernel 4.20 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1811159/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp