How much are you looking to spend? You can go with something lower end like a Hyper 212 EVO that should be good enough for overclocking or you can go with something high-end from a company like Noctua.
Never really heard anything about Phantek coolers which ones are good and how do they compare to Noctua D14. That's the one I have always heard to most about and it was almost always positive.
Ya the corsair sp120 will really help you should place it in a direction so that it push air inside the heat sink. and the original CM fan should pull hot air outside the heat sink by reversing the fan back to front.
Would putting a corsair sp120 improve the cm hyper?
Ya the corsair sp120 will really help you should place it in a direction so that it push air inside the heat sink. and the original CM fan should pull hot air outside the heat sink by reversing the fan back to front.