Doom is an prime example of a company and developers that absolutely spent all their time designing an engine for essentially one thing, optimising the absolute piss out of it. I remember doom 2016 launched without vulkan, was limited to basically opengl... it wasn't until i think 6 months later they released a "beta" implementations of vulkan that resulted in every ati/amd card capable of running vulkan hitting warp speed while nvidia's offers saw worse performance trying to run it, which is no surprise considering vulkan is mantle and nvidia refused to have anything to do with mantle, and their cards weren't being designed for it nor directx12 because directx12 was essentially a carbon copy of mantle as well.
Doom basically solidified what vulkan could do, and force nvidia and even intel to pony up and get to work on doing it right.
