either USB2.0 or Firewire are fine for dvd burning (though i've not used Firewire myself, no need as i've always been more than happy with USB2.0). I do all my burning at 8x and can quite happily (and very often do) up to 3 simultaneous USB burns using Nero's 'multiple recorder' feature ie burning the same movie or data to 3 or 4 burners