AMD specs the GPU at 210 watts.
The CPU spec is 65 watts.
I would say 200 watts for everything else is being generous.
So I'd say a 550 watt would probably work.
ASUS recommends 750 watts. I think that would probably be overkill....but ASUS doesn't know what people have in their systems.
I always go big with PSUs because the larger you go....the less stress the components see for a given load.