I'm currently running the EVGA 680, as well as an MSi 260 from my last rig as a dedicated PhysX sans SLI. I've heard SLI with such vastly different cards will reduce performance. What I want to know, is whether this is true or not, and whether it would be beneficial to run my 260 outside of Dedicated PhysX mode. So, SLI; yes or no, 260 for PhysX only; yes or no. A little explanation would be great too, maybe help me understand what I can do in the future.