I have the asrock h110 13 gpu board with a 1300w evga psu and a 1000w cheap Rosehill. I had mostly everything under the evga but tried spreading it evenly between the 2 and still freezing up. I hooked up a power monitor and when I start claymore it doesn't go over 200w and freezes no blue screen or anything.
Are all the cards properly recognized in the device manager? No exclamation marks and stuff like that? Are they software "accessible", can you monitor them with programs like GPU-Z, HWInfo etc?
Do you have spare risers to check the new cards with?