So if you have been following Vega at all and hoping it will be great for mining then you probably saw the leaks in the last 24hr. The leaks suggest that Vega is currently edging out the 1070, now you may think why is this good? Well this leads us to thinking there will be multiple varients of the Vega cards, this could be the low end Vega and we could get a starting price of $250-$300, since the 1070 is $340 and AMD has to be ready to combat a price drop anytime. A low end Vega card may also just be binned higher ups (this is was and has done historically with their CPUs and it could go with their GPUs as well) allowing for great hashrate with lower wattage.
yeah I suspect a Vega clocked higher will edge out a 1080 (not the 1080 with the GDDR5X)
I see Nvidia refreshing the 1070 with the faster memory in response and cutting production on any 1070/1080 that does not have GDDR5X which should already be happening for the 1080.
If that occurs, I suspect there will be price drops or a little price war between the two for non-GDDR5X models