Turning to the Antminer E3 -
Antminer E3 180mhs for 800watts = 1mhs per 4.44watts
RX Vega 64 43mhs for 134watts = 1mhs per 3.11watts.
RX 580 29.5mhs for 98watts = 1mhs per 3.33watts
RX 1060 24mhs for 90watts = 1mhs per 3.75watts
6GPU RX 580 191MHs for 950W = 1 mhs per 5 W - price
3500$those calculations are not correct. First you calculate hashrate per GPU W per GPU cards... its like comparing oranges and tomatoes no ?
you must calculate and compare the whole 12 card or 6 card rig to the beta Antminer E3.
where is F3 comparison ?
and my 2cents... If ethereum devs dont care for their miners, Miners should care for ethereum no more...
In answer to your wattage usage for the RX 580s - after doing the memory mod, memory OC and if the necessary pixel patch.
setting 950mv - gets you to 122watts for around 30.05mhs
setting 895mv - gets you to 98watts for around 29.5mhs
Varies from model to model.
Here is a basic guide for memory mod, memory OC, and mv950 30.06mhs on one model of the RX 580 8GB:
https://cryptoyeti.com/msi-rx580-armor-8g-review-and-bios-mod-guide/3/
And, as the reviewer does note - the RX 480 versions have even lower power consumption than the RX 580s for similar mhs.