I have a Dell XPS 15 Touch running Kubuntu 13.10 64 bits (and windows 8.1 but it is useless as OS).
The machine is awesome: new i7, 16gb of ram and full SSD. This thing is flying!
But I also have a dual video card: a system with an Intel and nvidia card side by side called optimus.
Nvidia choose to NOT support this on Linux.
So as Linus below (check the video, it’s worth it) :
Nvidia Fuck You!