Found this on Bjorn3d.com, just sharing it so don't flame me if you have a problem
There are two phrases that sum up the Noctua NH-D14: monstrous size and impressive results. We sort of expected the NH-D14 to perform well because of its unusual size and what we had experienced in the past with other Noctua heatsinks. However, we were not prepared to see 6~7°C decrease in cooling over one of the best coolers we have tested—the Prolimatech Megahalems. Our tests also show that even with a single 120mm fan placed right between the two cooling fins, its performance marvels that of the Megahalem. Making this the best cooler we have ever tested for Core i7 CPUs.
Source:
Noctua NH-D14 - Bjorn3D.com