just use the nicehash profitability calculator (https://www.nicehash.com/?p=calc ). Select your gpu or the gpu you are looking to buy. It will tell you how much power the gpu will use, what will be it's hash rate, What will be your Return on Investment (RoI), your profit and how much you will be making on daily basis
Hope that helps :)
RE: The best Cryptocurrencies to mine with GPU/CPU right now