I wouldn't go 550W for that configuration, absolutely no way! I think my suggestion of the Seasonic x-760 should be good, after your RMA the Corsair of course. Its technically a level upgrade since the Corsair AX750 (up from HX750) is based on the old x-750. That said, it all depends on the prices. Locally there is isn't too much of a price difference between the HX750 and the X-760, and I can tell you which one I would rather have. Very happy to pay an extra $30 for the x-760. If the total power use of a system is say 650W absolutely fully loaded, you should get a 750W at least. Sure, the 650W can handle 650W, but ideally you never ever should run a PSU at 100 percent. Its just like a car. A car may be able to handle 200kph, but driving at 200kph it won't be running at peak efficiency, nor will it last as long as driving it at 120kph. For what its worth though, regardless of lets just say, the questionable 550W recommendation above, and others with higher recommendations, your power supply shouldn't have blown.