After upgrading to 14.04, I had problems getting xbmc working I had problems getting XBMC work with my nvidia card.
Problem: DTS-HD/Digital audio passthrough using my HDMI via my AVR did not work.
Fix: Remove pulseaudio … yes.. really !
apt-get remove pulseaudio
(and don’t forget to restart)
Problem: Video tearing
Fix: To /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf, add -bs:
xserver-command=X -bs -core