Put this system together last week. AMD FX-6300 MSI 970A-G43 8GB Gskill Ripjaws 2x MSI R9 280x Running 3 tasks per card, getting about 400,000 ppd from each card daily. GPU time varies from 70-110 sec per task with very little cpu time 24sec or so. https://milkyway.cs.rpi.edu/milkyway/results.php?hostid=723824&offset=0&show_names=0&state=4&appid= But goodness does the top card run hot! 80-85c with a side 140mm blowing on the cards, case is well ventilated. Makes a nice bedroom heater through this small cold snap. But I am betting I'll have to shut down for summer or smoke the cards. May try 1 task per card when the time gets here, just to see if I can keep it up. I'd like to hit 100 mil first.