Stock cooler will be fine if not overclocking. Getting a 3570k and not overclocking is a waste. Especially when it is so easy. Set the multiplier to 40, leave all the voltages on auto and instant 4.0ghz without any effort. I use a coolermaster hyper 212 and no heat issues. I know a guy with same cpu and overclock using the smaller 92mm version of my cooler and has no issues either.