Benchmarks (Vulkan): Doom (+ frametimes)
Doom (2016) can be played in both OpenGL and Vulkan mode, two open-source API's that differ in the same ways as DirectX 11 and 12. The use of Vulkan leads to significantly better performance, particularly with AMD-cards, which show better performance games with well-optimized games using low-level API's.
Even a GTX 1070 is sufficient to get a great framerate at Ultra HD Ultra, but you get almost 120 fps with the GTX 1080 Ti. Using two GTX 1080 Ti cards only leads to lower framerates.
Here you can see the 99p framerates for Ultra HD Medium en Ultra.