I purchased this one today
https://www.superbiiz.com/detail.php?name=ZT-G1080TFcost me 720 and I get a very small discount of 14 so 706 net.
If I down clock a one card rig at the wall should be 200 watts or less doing 600 hash.
I have 16 rx 480's doing about 4500 hash and about 2250 watts
and 2 rx 480's in 1 rig at the solar array
so 3 h to 1 watt = nvidia
and 2 h to 1 watt = amd
I won't go all nvidia but I think adding two two card rigs is a no brainer
You need to understand I have 7 mobos running
I have 2 idle mobos fully ready.
Most people are not going to build a two card rig from scratch. I am building not building 2 card rigs
I had 11 four card rigs I sold off all my rx 470's leaving me with 18 rx 480 8gb cards using 8 rigs and 3 empty mobos ready for cards.