There's no reason to test a GeForce GTX 1080 Ti at 1920x1080; at that resolution, even our high-end host processor bottlenecks performance. Rather, these cards are designed for 2560x1440 and up.
At QHD, the Aorus GeForce GTX 1080 Ti Xtreme Edition 11G is, depending on the game, between eight and ~11 percent faster than Nvidia's GeForce GTX 1080 Ti Founders Edition or the Titan X (Pascal).
At this high resolution, Aorus' GeForce GTX 1080 Ti Xtreme Edition 11G is between eight and 10 percent faster than the GeForce GTX 1080 Ti Founders Edition and Titan X (Pascal) cards.
Many of these titles are playable at 4K. Those that aren't can be made smoother by dialing down the quality settings somewhat.
MORE: Best Graphics Cards
MORE: All Graphics Content