Been slowly building up my first miner, and at 4 cards it was fine, now it's up to 7 and it keeps crashing after about 5 minutes of use. It will hard lock up with the screen completely frozen. It's on 2 1000w EVGA power supplies.

If there wasn't enough power on the circuit to power both supplies, wouldn't it just trip the breaker?

Any idea what else could cause this?

It's on the ASRock BTC+ motherboard using mintcell risers with included cables.