I'd really recommend getting an aftermarket cooler. The liquid cooling ones (like the H100i) are a bit pricey but they perform just as well as the best air coolers (if not very slightly better). The disadvantage is that you need a case large enough to fit the radiator and fans in. There are some single fan liquid coolers like the H80 but they won't be as good at cooling compared to the bigger models.
In my opinion for liquid cooling get an
H100i with an extra set of fans if your case will take it, else get an
Noctua DH-15 air cooler (again, you may need a larger case to fit it in as it is quite tall).