The VRM power delivery circuitry on the reference RX 480 printed circuit board is beyond impressive. More so when compared to the GTX 1080’s 5+1 power phase design which simply pales in comparison.
The RX 480’s on-board VRM – voltage regulator – on the high-side is capable of delivering 40 amps from each phase at 125c, for a total of 240 amps.
At room temperature each phase can deliver 66 amps for a total of 396 amps on the high-side and up to 600 amps on the low-side. The
GTX 1080 Founder’s Edition voltage regulator can deliver 30 amps at 125c from each of its five phases, for a total of 150 amps on the low side, 246 amps less than the RX 480. At room temperature it goes up to 50 amps per phase for at total of 250 amps, 350 amps less than what the RX 480 VRMs can deliver at the same temperature on the low side. The GTX 1080 actually employs “doctor” mosfets which combine the high and low side into one IC. Hence why the PCB can get away with one mosfet per phase rather than needing two.