Closer Look at the Cooler:
The Noctua NH-D15 looks fairly similar to its predecessor after a quick look but on close inspection, one can notice several changes. To begin with, the overall design and feel of the NH-D15 is quite edgy and rectangular however the Noctua NH-D14 has curves on its sides. So despite being larger, the NH-D15 actually feels a bit more compact and smaller.
On a close inspection, I also noticed that the NH-D15 is actually a fusion of two NH-U14S coolers. The fin towers have very similar design and some further investigation revealed the each tower of NH-D15 is exactly the same size as the one of the NH-U14S. When compared to the NH-D14, the new CPU cooler is 5mm higher, 10mm wider and 5mm deeper.
The extra dimension goes into the size of the fin arrays. These are wider than the NH-D14 and the extra width provides more space for the heatpipes. However, since the number of heatpipes is still the same at 6, the extra space is used to put these 6 a little bit away from each other. This helps in spreading the heat more evenly among the fins.
Number of fins have been also bumped up to 44 from 42. However, the spacing and thickness of the fins is still about the same. To enhance the memory compatibility, the fin stack is recessed from both outer sides. Basically, the bottom 6 fins of both towers are smaller as compared to upper fins. This provides for up to 64mm of clearance for tall memory sinks in single fan mode. You can also take advantage of this space even in dual fan mode if memory slots on your motherboard align perfectly below this recessed area. This way the memory sticks will be hidden below the cooler. This is a very clever and useful design choice by Noctua. A long motherboard compatibility list of the NH-D15 is present on Noctua’s website.
The fins slope towards the centre either side of both towers. This lowers the wind turbulence and it also helps in minimizing the airflow dead zone created due to the central fan hub.
As always, the finish on the NH-D15 is great; it’s neither chrome nor matte but it’s the perfect combination of both. And it not only looks good but gives out the feel of sturdiness, durability and quality too. The fins are also solid enough to handle minor bumps and pushes.
Despite the trend of bases with mirror-finish, which some modders even achieve by lapping, Noctua has stayed true to the opaque finish.
The bundled Noctua NF-A14 fans are very interesting. These are basically 150mm fans in frame of a 140mm fan and have mounting holes of 120mm fans. They come with PWM motors with speeds of 1500 RPM at max. Furthermore, these are equipped with self-stabilizing oil-pressure bearings, which insure silent operation. Fins on the NH-A15 fans have flow acceleration channels, which lead to better efficiency and lower vortex noise.