Previously my system contained 3 GTX 980's, I sold 2 of them and bought a Titan X. I have been running it with the Titan as the main and the 980 as dedicated Physx. Would I be able to SLI these for a slight speed-up whilst still having the 980 as dedicated Physx? It has been running this way for nearly a year, and I plan to implement a custom sub-zero liquid cooling system in the near future.