Hello,
i thought about building a mining rig with 3-6 MSI Radeon RX 580!
What do you think which altcoin i should mine and how many profit i could make?
Energy costs are 0.14$/kWHT
Congrats on the plan to start mining!
First off go with RX-570's instead of the 580 as it will be slightly cheaper and with the proper BIOS mods will produce the exact same hash rates.
Second, don't listen to anyone saying "it's not profitable". Even at .50 kw/h it's still profitable not including any future rise in value. Mining profitability is always underwhelming on paper but you rarely if ever hear of miners quitting or going broke. Given the up front costs it may seem like you wont ROI very quickly, however the cards have value themselves and if the past is any indication the Crypto you mine will increase in value effectively increasing your daily profitability.
Third, right now for AMD RX-560/570/580's the most profitable coin will be Monero, assuming you correctly modify your cards to maximize their potential.
Use this tool as a good place to start:
https://whattomine.comGoodluck and welcome to the muscle behind Blockchains!