I can confirm this behaviour, also x86-64. In particular, after enabling all the possible memory columns, all the memory usage seems sane except for "X server memory" and "Memory", which is, as the reporter states, 17179869180.0 GB, and this figure is the same across all processes showing incorrect numbers.
A list of all these processes, in case someone can see a common theme, is: gtk-window-decorator multiload-applet-2 empathy nm-applet nautilus gnome-panel gnome-system-monitor gnome-terminal deskbar-applet ** Changed in: gnome-system-monitor (Ubuntu) Importance: Undecided => Low Status: New => Confirmed -- Certain processes show incorrect memory usage https://bugs.launchpad.net/bugs/148325 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is a bug contact for gnome-system-monitor in ubuntu. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs