You're doing it again, reading something and then applying your own slant on it, by this measure your prediction is even more out.
Given that Fiji is a 250 Watt card; if Polaris is a 250 Watt card it will end up 2x the performance of a Fury-X
Half a Fury-X (Fury-X performance at Polaris power consumption) is 125 Watts
So lets do the Maths.
Polaris at 125 Watts = Fury-X performance
< 2x the performance per Watt
Polaris at 190 Watts = 1.5x Fury-X performance
< 2x the performance per Watt
Polaris at 250 Watts = 2x Fury=X performance
< 2x the performance per Watt
whats the power-consumption of P10? is it 50 watts?, or 150 watts? maybe 200 Watts?
no body knows.....
Do people even bother to think about they are saying anymore?
We do know this, the 125mm^2 P11 is a 75 Watt GPU, so the 235mm^2 must be about 135 Watts? so that must mean P10 is 1.15x Fury-X, right? No.... we don't know enough about anything to draw conclusions like that.
Oh but wait a minute, the Fur-Nano is only a 150 Watt card and is only about 15% slower than a Fury-X, now i can argue we will have 3x Fury-X performance with Polaris 10! yay for AMD fans.....
What a load of old.....