It's hard to help you if you dont describe exactly where you're getting a black screen at. Did 4 cards work fine with 4g disabled? Did 5 install and code 12? Give details.
It goes straight to black screen right after the loading circle, which comes after the bios image. (the part where it shows the mobo maker and press del to go into bios). So up to now its been black screen. I left it on for the duration.