Check the whattomine.com if what altcoin is more profitable to mine with your rigs since your electricity is free you can earn without paying electricity].
Try to mine etherium with your card use claymore.
try follow this guide
https://bitcointalk.org/index.php?topic=2126975.0Thanks for your advice.
I have no experince about mine eth. How about minimum payout, so how long we will get first payout from pool? Why almost all coin use xmr tittle for miner?
Minimum payout will depend on the pool. I think ethermine.org probably has the lowest payout of .01eth threshold