Noctua's own overview of the cooler:

Combining a massive six heatpipe dual radiator design with an exquisite NF-P14/NF-P12 dual fan configuration, the NH-D14 is built for ultimate quiet cooling performance. Topped off with a tube of Noctua’s award-winning NT-H1 thermal compound as well as the new SecuFirm2™ multi-socket mounting system, the NH-D14 is an elite choice for the highest demands in premium quality quiet cooling.



Noctua have gone all out to create a no-compromise solution with the NH-D14. The main features here are the dual radiator design, as seen in the Thermalright IFX-14 and the Tuniq Tower 120 Extreme, and the dual NF-P14/NF-P12 fan setup. The aim here is to create a much higher dissipation surface area over which the two high performance fan can efficiently transfer the heat, while still retaining low acoustic level. Instead of a brute force approach of using high RPM fans, the low speed dual 140mm/120mm fan design helps Noctua achieve what they are best at, high performance without sacrificing your hearing. The 140mm fan is also oriented in such a way that it cools the surrounding components on your motherboard. Often, the Northbridge and Mosfet cooling are forgotten when overclocking, thereby limiting your headroom so Noctua hopes to address this problem.

One thing to take notice though is that the NH-D14 weighs over 1kg with both fans attached! This is heavier than other coolers we have tested before but we can sleep well knowing that Noctua's SecuFirm2 is class leading for a very good reason.