I leave everything at the defaults becasue that is what Hitech came up with as the best compromise for the broadest number of PC configurations. I spent two years testing all the possible settings for him and unless I'm going to spend a lot of time in a tank, I leave it at the defaults. With tanks everything to the max will get you the ability to use german optics to three miles. Maybe four. It certainly will help you resolve tanks from trees and leaves better inside of three miles.
I looked at the specs for the TitanX in the 1000series family. That monster shouldn't have a single bilp with anything you run for this game. You are way beyond the bandwidth, shaders, and data path issues that would matter. Yet, that is one of the reasons players have FPS issues becasue they are not aware that a 192bit bus can have FPS issues where a 256bit bus like my GTX760 won't. Depending on the texture level they are running and how far past the defaults they have pushed the sliders. During the alpha\beta I kept track of graphics card issues posted by other testers to come up with some kind of a base line common standard. I also tested with a GX9800, HD6770 and GTX760. As BW, Shaders and Data path went up, the graphics issues went down. Your TitanX is the Titan of the gaming world so I'm clueless at this point.
Have you talked to Skuzzy about this one, I seem to remember a few players with 980 and 1080 had FPS issues when those cards have the grunt to blow the game away?