12 1060 micron (no strap) @ 635mV (little bit more efficient then pl 70)
How are you able to set low voltage like that?
In my afterburner in curve editor voltage starts from 800mv, so there is probably a different way

I am guessing its a typo and maybe he meant 935mV. I've tried different voltages and I think its impossible to be able to run it that low and even get Windows to load.
He might get lucky and have an extremely high ASIC quality however its not possible that 635mV would be enough to mine with.
With the RX 470/570, they generally need about 120 Watts (from the wall, not including cpu+ram+mobo) to run without hardware error or hangs. If you want it to use less power you need to mine an algo like XMR which uses like 100 Watts.
not a typo and i have replied to him, obviously amds are crap with about 1/2 efficiency per watt
in nvidia inspector you can go as low as you wish, 650mV is not as low as it will go
However after the straps I have problem on two rigs, one card is crashing on each, I have even tried settings like this
-strap 1,1,6,1,1,1,1,1,1,1,1,1 -sintensity 100,100,2,100,100,100,100,100,100,100,100,100
-strap 1,1,0,1,1,1,1,1,1,1,1,1 -sintensity 100,100,0,100,100,100,100,100,100,100,100,100
and 0 mem OC, and even disable undervolting
then cards now gets about 20MHS and still crashes, while before with ethminer or phoenix both cards could get 23 or 22mhs undervolted overclocked
Well no rig is truly stable now, but that is expected while finding new OC values, best I got was 22h58m uptime while before the straps months
Maybe just first dead GPU, but so far these things were unkillable.