I read that here: https://bethesda.net/#en/events/game/the-graphics-technology-of-fallout-4/2015/11/04/45
Now that explains a lot about the System Requirements of the game, and solves the riddle of why the game requires a considerably more powerful AMD gpu to run than a nVidia card.
Oh why dear Bethesda Games Studios do you get yourself in to a fight between hardware vendors and don't you stay neutral ?
Its not nice getting punished with worse frame rates in the game you made because I chose a graphics card from a different manufacturer.
And bringing in mind the tactics of unwanted competition that have taken place in this hardware war, it makes it even worse.
So what is it going to be now ? 24x tesselation in some invisible mesh that cripples performance on AMD graphics cards and can be turned off with zero impact on image quality but a huge one on frame rate ?
I have AMD cpu and gpu and I wouldn't like it if you decided to add AMD's similar kind of stuff like TressFX either. Neutrality is the best and more just option in this case IMO.
I'm disappointed.