Thanks for sharing, what are your voltage settings ?
R9 290 is Gigabyte and its voltage lowered in Afterburner to -50mV and can even less (bios also modified 1000MHz timings for 1250 and 1375);
R9 290x is reference flashed with Stilt V3E (DPM7 - 1.1625V);
RX580 is -60 mV from default (but recently Afterburner asked for reboot, I pressed Yes, and now voltage control is missing for rx580);
That's all I can say about voltages.