Tried 2.7c for 10mins. Within 1 min, 1 of my RX580 dropped from 30.5mh/s to 24mh/s and remain at that speed. Temp same as using ver 2.6. Infact I used same bat. file as ver 2.6.

Revert back to 2.6 immediately and hashrate goes up to 30.5mh/s for that gpu. My rig consist of mix of gtx 1070s and rx 580s in one rig.

Will continue using 2.6 until 2.7c becomes better.