I agree this is probably where it started but it makes no sense to me. We know that for whatever reason AMD has not "scaled" past 64 compute units and we also know they can't sit at 64 compute units forever. In my mind the most likely interpretation of "Scalability" for Navi is just that it will...
Maybe it's 99th percentile frametime converted to FPS? I guess we'll have to wait and see if the devs comment on why Vega seems to be doing so well.
Agreed about the Fury X 4K numbers probably tanking due to limited framebuffer.
Looks like the Nvidia cards are underperforming rather than any Vega magic, the RX 580 has a higher 99 percentile result than the 1080 Ti @ 1080p. Maybe some NV DX12 driver hiccups?
Bit-tech has some new DX12 numbers up for a 1080Ti review that includes Vega 56 and 64.
https://www.bit-tech.net/reviews/tech/graphics/asus-geforce-gtx-1080-ti-rog-poseidon-platinum-review/7/