Thanks for the answers. RX 570 would be a good choice but I can't fin them easily (and maybe having more than 4gb RAM would be a good choice). What kind o performance can I have with a 6 x Gtx 1070 rig (in mh/s)?
All the market in the world you would not get the Rx 470 and 570 cards not easily from the local market. Please check the authentic reseller of the Radeon cards in your city and do prebook. Even I have done the same thing to order a cards.
Last time tried order, 6 RX470 cards but price was little high and not available instantly. He asks me to wait for some weeks and finallly I got after 10 days. Please check local reseller as I said.