Assuming a rough average clock of 1150MHz for the reference card, the PowerColor card would need an average clock of 1380MHz (and a memory OC too) to get 20% better performance. My concern is the card would be drawing well over 200W doing that. Admittedly it would be performing like a moderately overclocked GTX1060 at that point.
Rogue Leader, don't say AMD is out of the game yet. AMD is the only one with any pieces on the board so far. We'll see how the GTX1060 does in the real world soon enough. And whether it is actually available in meaningful quantities. Presumably from the same wafer size, AMD makes at least twice as many RX480s, even assuming none of the NVidia chips qualify as 1070s or 1080s.