^ out of that DX12 list, only two games (deus and hitman) run clearly faster on RX 480. They behave the same on DX11 since they are sponsored by AMD.
on the other hand, rise of tomb rider, quantum break run clearly faster on GTX 1060.
So the DX12 advantage of AMD is kinda urban legend.
It will be like with any other API - some games will favor one vendor, others will favor another. Considering deep nvidia pockets and larger marketshare, guess there will be more nvidia optimized games.