That will depend on voltage needed to get to 4.6. More than likely it will be fine
Best practice is to buy the best you can afford that will give you the performance desired, in my case I wasn't satisfied with an Hyper 212 EVO and went straight to NH-D15S. Once again this wasn't good enough so I delided my chip.
And thats the problem with overclocking, if say you hit 4.6 comfortably with the h7 whats next 4.8? Certainly raising the voltage now and more than likely the h7 will let you down.