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I don't understand these prices of card going from 100 to 1000$. Will be going for NVIDIA for altcoins. Maybe 2 cards for the start. Celeron, power supply and 4 gb RAM. My opinion is that it's better to mine low price and difficulty coins like Siacoin et cetera.

Check out nicehash.com for comparisons and projections of returns for various cards

I got a Sapphire RX580 Nitro+ Limited Edition at 27MH/s, estimated to mine 0.01X ETH per day. The whole setting consumes ~500W/h (it would be more power efficient in multi-GPU), you may take mine as reference. AMD is saying to be better than NVIDIA based on the power efficiency. You can see the higher hash rate of 1070 / 1080, but the price is higher as well.