I bought 36x 580 8gb for 700,00 each...
I think Im going to have 1 year to 1-1.5 ROI.
But I thinks is going to be a good investment.
Lets hope it is!!
I think you bought very expensive and now bad moment for start mining
But if you believe you will be get good profit in future
I am prefer Nvidia cards)
The nVidia cards are more power efficient. So they are good for people with expensive electricity prices.