Are there any errors in the system log? Maybe the kernel log?
there was errors but I don't know what to make of them
Also, what are you using for a PSU?
650w, antec earthwatts, 80plus bronze, dual 12 volt rails
dual rails can be an issue - are you sure the load is split properly, not 400W off a single 300W rail?
also, you dont need the 'stratum+tcp' i just use us1.ghash.io:3333