The rx560...seriously? How many MH can it pull in ETH?
15.5mhs with 1300/2100 clocks at 60w, basicly half a RX470
tweaked 570 = 27Mh/s @ 91w at the wall (64w on gpu-z). Could be >29Mh/s >100w but my elpida does not clock enough.
Model and memory?
asus expedition. Elpida (1850mhz max).
eth only= 1090/1850mhz @ 831mv = 91w (wall)
Dual mining = 1130/1850mhz @ 831mv = 118w (wall)
I have Elpida Stritx OC 570. Will try your settings. I have 26.5 Mhz and hihger power consumption. Also it is the hottest GPU in my rig with %100 fans all the time.
I really need to tweak it. Which strap? Any special strap value? @831mV for GPU or MEM undervolt?
Thanks.
Like Mattthev said, depends on your chip quality and temperatures. I've seen people here with less than 800mv on rx580!
Here's the bios I use (the strap I use is selected and visible).

About the fans being 100% all the time, it was happening to me too on my temporary case.
These "open" GPU's are blowing hot air in every direction. Make sure your cards are not blowing hot air in the direction of the motherboard, because that hot air will bounce back and heat up the neighbor GPU's, which in turn will heat their neighbors even more.