if you want to build a new one

prefer to build a Nvidia rig.
go 1070 or 1070ti first.  (you can choose 3 fan models for more cooling and silence)

if you want to build a ethereum rig with maximum performance/price ratio, you can find and collect  Rx470 8 gpu's in second hand from gamers,  (8g are very rare).  Or you can find a second hand rig.  they are best for ethereum.  maximum performance/price lowest wattage/hashrate.


But my choice would be for the  gtx1070 in second hand.