For an i5-4670k (assuming this is what you're getting if you choose Intel), 4-4.3 GHz is relatively easy to achieve with a CM Hyper 212 EVO. Just depends on your chip, you cold get a golden chip, and you could get less than optimal chip.
I'm not sure about the AMD side, so I won't really comment on that except that anything above a 8350 isn't really worth the money, as you could get similar performance from an overclocked 8350 (8320), or outright just get an Intel.