So decided to create this thread for the RX 480.
I have tested this card with underclock, overclock, and have found the new Wattman in the Radeon Settings to be quite good.
Stock settings the card does exceed 150watt usage mining at 24 Mhash
Underclocking the card to a core of 1100 brings the watt down by 30 and yielding 23.5 Mhash (GPU-Z reports 0.987 Volt)
I would say its the best config of everthing that I have tested.
Overclocking it to 1350 core and 2200 mem with powertune + 20 I yielded a 26.5 Mhash stable but this will probably fry your motherboard as the card reaches 175+watt.