I has 15A on my 12v. 1 SATA drive, 20+4 mainboard power-connector, CPU/FAN, and I think that's it.
So all is good then?
Actually, would a 4670 have the same power requirements? I can't find a DDR3 model of the 4650 anywhere..
The 4670 has a TDP of 70W, the 4650 has 55W, you'd be fine with the 4650, but I recommend against getting the 4670 with only 15A.