AMD demonstrated Vega running Doom 4 with an FPS counter a while ago, and it was running about 10% faster than a stock GTX1080 (non-ti) or on par with an overclocked GTX1080.

Doom 4 performs unusually well on AMD cards compared to other games, so on average Vega is probably similar to a stock GTX1080. Which leaves them with no answer to the 1080ti :(

I think Doom 4 performs so well because ID software usually has one of the most optimized engines (for everyone) and I believe that AMD cards have more raw power then Nvidia, but it's usually unused(I think due to unpopular APIs). Thus Nvidia is generally known to perform better in real world cases.

I personally believe the top end vega will fall just below the 1080ti.

That's based on what exactly?

So far I do not believe they've shown enough for us to know it to be either way.

Which is why I said personally that is where they will fall. Just from looking at leaks and the same source of the RX Fury leaks it seems like that is where it will be.

Whoever submitted the values, if by mistake (not a plant), is definitely running neither final production clocks nor drivers.

It might have some credibility if it was 2 weeks away from release, which is definitely not the case here.