Indeed if you love overclocking then for Good safety get an aftermarket cooler, something like Hyper 212+, Stock coolers aren't very good when it's come to overclocking 212+ cooler is very very popular and still very good for overclocking.
Overclocking is very risky task many users blow up thier cpu's due to no care of voltage, First you need to know complete procedure for overclocking then proceed to it, also temps is necessary too.