On Mon, 2013-12-09 at 19:08 +0000, Tom H wrote: > The Ubuntu-created grub.cfg cannot be blamed for a GDM problem. If GDM > is being launched, grub's job has been done many seconds ago. This seems to be true here, but you're mistaken, a boot option could still cause something when a DE session already is running, e.g. "threadsirq", "noatime", sure, "noatime" won't brake something, but "threadirqs" at least could slow down GUI performance, assumed it's a lowlatency kernel.