No, a 650w quality psu with four 6 pin pcie connectors is fine(, both the links i gave you have more than enough juice for your system.
The 1º one is a 750w plus silver semi-modular made by seasonic(best quality brand of psus) branded design with xfx, which is more than enough.
The 2º one is a 650w plus gold modular seasonic, which is also more than enough for your system, it can pull more than 650w.
I wouldn't go with the ocz, it has multiple +12v rails, it's worse than the seasonic x-650w and i bet it's about the same price.
I will consider that and I will buy a seasonic probably the one with 650w...
I can also tell you that i have one seasonic now in my PC and I am happy with it,so thank you you were very helpful.Have nice holidays!