The generated heat is in direct relation to the overclocking method you choose to use, there are various ways to overclock the Sandy Bridge CPUs, some using all Intels features, some partially using Intels features, and some using basically none of Intels features.
The latter method, the overclock guide I wrote is a maximum heat generating method, which in the beginning was very frustrating attempting to keep it cool enough to run all 4 cores without throttling, below is my cooling solution.
I'm not suggesting you take that route, but just so you can see what I tried that didn't work, and some of those that didn't make the grade are better coolers than the H50, like the Rasa 240 loop and the Thermalright 120 extreme with 2 2000rpm fans in push/pull.
http://www.tomshardware.com/forum/267412-29-sandy-bridge-water-cooling-project
The bottom line is simply a No-Brainer, the cooler you can keep it, the further you can overclock it, no matter what overclock method you choose.