I'm beginning to believe my motherboard is not capable of handling more than 2 cards ugh! Msi z170a gaming pro carbon either on boot (windows 8 or 10) doesn't recognize cards, afterburner doesn't show temps and card crashes or opencl hangs on miner
I got a Z170 board not knowing issues. It will see and mine with 4 GPUs no problem (470/480), though if you try 5, it will lock up at bios, even though board has 7 slots. I have
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128838 Then I just decided to get H81 BTC pro boards (harder to find).
This MSI Z97 works just as good as an H81 BTC - cheaper in most cases - plus it has 7 pcie slots - I have 2 rigs with this board and 7 RX480's each. Works great.