Honestly this is the first time I'm hearing about biostar 580s, all I knew about biostar are motherboards not GPUs, anyways you should get hiveOS for those GPUs and use the right OC settings in the hive OS to get the best hashrate out of the cards, use Core 1150 and mem 2050 this is how I achieve 30mh on mine
Biostar has GPUs too. Yes, I am managing the cards in Hiveos actually but whatever tweaks I used so far didn't work!