NH-D14 is more than sufficient.
http://www.tomshardware.co.uk/forum/273667-11-overclocking-bulldozer-8150
Here is the best answer i take no credit for dormantreign's answer
1. Be prepared to BSOD
2. Turn off all power saving functions in your bios
*Cool n Quiet
*Turbo Boost
*Spread Spectrum
*Anything else that is related to powersaving, i don't think Spead Spectrim is power related but turn it off anyways.
2. Gain access to your multiplyer and being the push upwards 14X>15X>16 and turn off (Auto) voltages for your Vcore and lock your ram at 1333 or 1600. If you can't just use a divider on it and drop it near of below its specs but keep the voltage set at its default.
3. Boot up your system to see if its stable or BSOD'ing on you. Do quick checks with CPUZ and monitor your tempatures.
4. Once you reach you're maximum, you can up the voltage on the process, but don't go up to much, use small increments to see if it stablizes and stops the BSOD or freezing.
5. Lock and load!, Thats be basic's!
* Sometimes overclocking via your BUS can't produce better results, that's the 200-399 near or around your multiplier, but it effects your ram on some motherboards so be sure to watch your dividers so you don't push your ram out of spec.
That's the very basics and should answer your question better then the "Search Google" answers here. That being said, google is your friend for fine tuning.
*Final Notes
Don't push the voltage to far out of spec!
Watch your temps!
Overclock can produce strange issues on a PC, such as BSOD when plugging in USB devices, and other rather annoying issues you can't track down. Sometimes to fix these issues you'll have to reset your bios.
Hope this helps!