I currently have OEM ATI 5870 and would like to add 3rd 24" monitor. One monitor is hooked up via DVI cable, second one right now is hooked up via HDMI to mini display port adapter. What do i need to connect 3rd monitor? I keep reading conflicting reports. My display has Display port connection can I just get a display port to mini display port cable and be done with it or do I need an active MDP adapter?