is it worth to make an rig next month? i pay about 0.08 cents per kw/h
you should roi in 3 months, assuming diff stay the same, and assuming your build will cost around $2k(6x390)
sounds about right, plus you will have resale value of 6 390s, which shouldnt be too bad even if the new cards come out. and after that its the end of ETH probably (for mining), but there will be more coins to mine

he can actually roi much faster if he sell his right or even take a big profit, from it