I know this is not a fair comparison, however X-Plane has released their Vulkan Beta. Using a 2080 Super, I'm getting an increase of just over 5% FPS. X-Plane indicated that Nvidia users weren't going to see a huge increase in performance. AMD users are reporting a bit more in performance based on what I've read in the XP forums. Again, for whatever this is worth. I wouldn't expect Vulkan to be the game changer some folks are hoping for.