Don't forget the the special cable needed for the third monitor. Mini DP to (DVI or HDMI or even VGA whatever one you need for your set up) And yes it has to be active 20-30 Dollars US or so
Check your video cards out puts first and remember the HDMI and one of the DVI outputs share the same port so you can not use both at the same time its a one or the other. (this is for the ATI cards)
