I have been doing mining for 1 year using Asrock H81 pro btc R2 . issues I've experienced:
1. When booting, Ram isn't detected, I did Move the DIM1 slot to DIM2 or vice versa. (solved)
2. 1 or 2 GPUs aren't directly detected but they can be solved by trying to move PCIe slots to other PCIe. (solved).