Is it possible to desiginate a gtx470 to be the main GPU and a gtx 280 to do only Physx rendering? I am have been doing some research but yet to find a solid answer. Just curious since I plan on buying a gtx 470 but would also like my gtx 280 busy.
I'll check on my PC tonight, but I believe there is a setting in the Nvidia control panel that will let you set physx on a specific card. I have dual 260's though, so I'm not sure if that same option would be available to different cards.
You can't put two cards of different models into SLI mode, but using two mismatched cards the way you described is possible. However, I don't believe FFXIV will be taking advantage of PhysX physics processing.