Hi all, Im running 2 27" Apple cinema displays on my 2012 Mac Pro Hex Core with the ATI 5870 card. I wish to add a third 27" Apple cinema display and whilst discussing this with the Apple store they tell me I need to add either another 5770 or 5870 card to the Mac Pro. I intend working off a Mercury Accelsior PCI Card when Mountain Loin debuts. Can all these 3 items fit? and if so do I need to keep the Mercury Accelsior PCI Card in a particular slot for best performance? Thanks in advance for your thoughts.