1. I have the same motherboard but a slightly weaker CPU ( FX 6350 overclocked to a very stable 4.3Ghz ) and it gives me no problems whatsoever. I could probably get it at around 4.5-4.6 no problems but I dont trust my cooling to be honest. For a tight budget, the Gigabyte 970A-UD3P is probably the best out there due to it's VRM.If you dont have any restrictions in budget than you can look higher up the class. Getting a FX 8320 to 5.0Ghz will produce an incredible amount of heat. Make sure you have a high end fan&heatsink and the best thermal compound applied correctly.
2.In wattage, 600 is plenty if you dont plan in getting 2 high end GPU's. The CX series of Corsair is however a bit weak.