Interesting. The majority of the game reviews tend to put the Vega 64 a step behind the 1080GTX, but then it does depend on resolution, at 4K the Vega does have a little edge. On the other hand, most reviews are all pushing max settings to try and report max FPS, and only a single game.

Still that is all just another one of the factors.

General conjecture, I would put the NVidia at a slightly better performer myself, BUT, I don't have one or a Vega 64, to give an actual comparison.