I would be suspect of BOTH PSU's. If you have anyone with a nice system, try borrowing a QUALITY 450W+ PSU. You are starving your GPU on the 12v rail. Did you try the CX430 WITH the 5670?. Also, how old is the 430?. I would suggest something like the Rosewill Capstone 450W as a starter for the 6850.
11/21/14 at 4:21pm