Hi there, I don't think that rx460 is currently profitable as it is wayback 2016 if you are planning to mine top 20 coins. There are now more appropriate gpu for mining, why not try 570s or 580s if your motherboard permits. Also, you should invest on the power supply, but a 750w gold or above for efficiency. You don't want to end up just paying your bills on your mining profit. You should also consider the electricity rates on your area as this will affect you profit.