Noctua NH-D15 Review (Page 2 of 4)

Page 2 - Physical Look - Hardware; Installation

A view from the top three-quarter view of the Noctua NH-D15. The latest version comes in a sleek matte black finish on all surfaces, which looks incredible. It took the company a year to develop, and they promise the new color will not reduce cooling performance. Color and finish aside, this heatsink is physically identical to the NH-D15. If you are familiar with the NH-D15, it was based on same form factor as the Noctua NH-D14, except the radiator design is essentially two modified NH-U14S stuck together. As far as engineering and implementation goes, fans can be mounted on using two clips each. Two Noctua NF-A15 HS-PWM fans are included out of the box, but only one of them is pre-installed for packaging reasons. You will need to take the pre-installed fan off for installation. These wire clips are easy to attach and remove in a uniform fashion. Integrated rubber dampeners on the included Noctua NF-A15 HS-PWM are used to dampen noise from fan vibration during operation, shown in our photo above.

The leading edge of the fins on the Noctua NH-D15 is characterized by its low angle V-shaped slope towards the center along with zigzag edges. This unique design, evolved from several generations of Noctua heatsinks developed between the late 2000s to mid-2010s, is made to maximize airflow between the fins with minimal resistance and turbulence noise. Furthermore, this causes a negligible decrease in heatsink surface area, which is important for heat dissipation. There are 38 full-sized aluminum plates and seven smaller ones near the bottom on each radiator to take advantage of the massive cooling fans. The gaps are reasonably spaced; designed to be a little less dense compared to the NH-U14S. From my calculations, the total surface area of all the cooling fins combined is approximately 1.2 square meters, which remains unchanged from the regular NH-D15.

The Noctua logo and branding is engraved on the top fin horizontally. The company specifies the NH-D15 at 980g with no fans installed. With one stock fan attached, it will tip the scale at 1150g according to the manufacturer. Adding a second fan will increase the weight to 1320g. I cannot call this heatsink lightweight by any objective measure, but considering the size, keeping it at just under a kilogram is a good figure. A heavy heatsink will stress your motherboard more than a lighter heatsink, but the effect can be mostly mitigated with a well-designed installation bracket, which Noctua has. Generally speaking, the material composition of the heatsink is crucial to the overall weight. We will take a closer look at the construction of the NH-D15 in just a short moment.

The Noctua NF-A15 HS-PWM fan is very easy to dismount from the radiator. Almost nobody in the right mind will replace the Noctua NF-A15 HS-PWM with a different fan, but it still needs to be removed during installation. The Noctua NF-A15 HS-PWM is an all-black version of the NF-A15 PWM, but otherwise the same fan. The attachment wires hook on via the outer side of the fan and secures onto the radiator by a two-stage clipping ledge for an easy and secure installation. From the angle in our photo above, we can see the clips are mounted over a two-stage recessed ledge integrated into the heatsink fin design. Wire clips are hooked directly to the fan instead of plastic clips. Attachment stability is not compromised, because the wire clip retention length is reduced to a balanced level rather than spanning the entire height of the heatsink like old Noctua products. This design advantage is obvious. It is easy to remove the fans with tabs in the wire and the clips can be removed in a uniform manner. This also permits greater flexibility in fan-heatsink location alignment for the user compared to the previous design.

Those who are familiar with the lineup will know the Noctua NH-D15 is a mega-sized heatsink. Six continuous U-shaped heatpipes lead away from the CPU contact base in two opposing directions for twelve effective heatpipes. Those heatpipes then go through two separate radiators, one on each side, to dissipate the heat into the surrounding environment. Theoretically, the heatpipes are supposed to efficiently lead the heat away from its source due to the low heat of vaporization, or phase change energy, of alcohol. The heatpipes are aligned in a linear manner to evenly distribute the heat in the radiating fins, as the NH-D15 series is really two reduced weight NH-U14S heatsinks stuck together. The Noctua NH-D15 come at the cost of physical size; its height of 160mm and width at 150mm is pretty standard, but its length is the one that makes it literally stand out. In standard configuration, with one fan mounted in the middle, it already comes in at 135mm. Add an extra fan to the front, and this figure jumps to 161mm. That said, with 1.2 square meters of surface area, combined Noctua's excellent NF-A15 HS-PWM fan specifically designed for heatsinks with a high amount of static pressure, you are definitely going to get some serious cooling performance and low noise levels -- something we will investigate on the next page.

There is a clearance room of about 6.5cm between the heatsink contact base and the bottom of the upper fin array. This is the area where the NH-D15 will extend over your RAM slots, and that is quite a bit of space. In fact, you can probably get some higher profile memory to slip under. However, if you choose to install the included optional second NF-A15 HS-PWM fan in front of the first radiator, all this clearance room will be no longer. The second NF-A15 HS-PWM will need to be mounted high on the heatsink, as it will interfere with any RAM regardless of profile unless you mount your NH-D15 in a non-standard orientation. Therefore, you will need a wide case with lots of clearance room between the motherboard and the left side panel.

A shot of the bottom of the Noctua NH-D15 CPU heatsink. The photo above shows the configuration of the heatpipes more clearly in relation to the base leading into the fin array. The contact base of the Noctua NH-D15 has a clean and flat finish for optimal performance. Like all Noctua heatsinks we have reviewed in the past, the NH-D15 is a copper and aluminum hybrid heatsink electroplated with nickel. The difference, of course, is everything is painted matte black other than the base. The vital parts such as the base and heatpipes are built using copper for best heat transfer ability with a thermal conductivity of 401 W/mK. The heatsink fins utilize aluminum as its material due to its lightweight properties as juxtaposed to copper. This is to allow the construction of larger heatsinks without stressing too much on the motherboard due to weight. Aluminum has a thermal conductivity of 237 W/mK, which is not as optimal for heat transfer compared to copper, but it is much lighter.

Visually speaking, the NH-D15 from Noctua has none of the copper color with its copper heatpipes and base. Everything is painted matte black other than the base as aforementioned. Even so, the Noctua NH-D15 is electroplated with nickel on top of its copper, which has a thermal conductivity of only 90.9 W/mK. Nickel has lower thermal conductivity than copper, which may limit heat transfer, but the electroplated layer is very thin and will have a negligible effect on cooling performance. The reason why nickel is electroplated on top of copper is related to its corrosion allowance factor. Nickel and nickel-base alloys have desirable properties that can withstand corrosive environments and high temperatures, which are especially beneficial for a heat dissipation device. Nickel is resistant to corrosion because of its ductility and toughness all the way up to the melting point of 1455°c at non-standard pressure. Nickel's face-centered cube crystal structure is virtually unaltered all the way up to that temperature. Therefore, the corroded material will not build up on the surface over time. This is important because the NH-D15 will be less prone to losing its cooling performance over time compared to a corroded copper surface.

Furthermore, all joints on the Noctua NH-D15 are cleanly soldered at the base. The heatpipes are soldered to the fins too, so it will not lose contact over time. Lower quality heatsinks often offer high initial performance, but may degrade over time as contact between metals decreases due to thermal expansion and contraption. Overall, the Noctua NH-D15 appears to be solidly built. Reliability should also be excellent as I have seen with every Noctua heatsink I have used since 2007, which retains its performance very well over time.

Noctua's installation process has always been simple, and the NH-D15 is no exception. Noctua packaged each set of installation accessories individually for excellent organization. Along with the clear and concise setup poster, setup was a breeze. This is not to mention I have used the SecuFirm2 system for at least a decade -- including the NH-D14, NH-D15, NH-D15S, NH-U12S, and NH-U14S. Needless to say, I did not need to read the poster in the setup process.

As you can see in my photo above, Noctua's mounting system on the Intel platform utilizes a proprietary backplate supplied by Noctua that installs over the stock plate for optimal weight distribution. The inertia generated by such a large heatsink is really something that needs to be addressed accordingly, otherwise it may simply fall out or cause excess stress on the motherboard. To install, simply align the openings on the supplied backplate with the screws of the motherboard's stock backplate, and flip the motherboard around.

The Noctua NH-D15 uses the SecuFirm2 mounting system, which has not been changed since the original NH-D15 was launched. Changes from the original design include a backplate with new mechanics as well as integrated bolts. Functionally, the revised mechanics do not change anything regarding its compatibility, but the integrated bolts make the installation procedure much more pleasant. The part number for the backplate, NM-IBP2, has the text "Rev. 2" underneath it. What exactly were the changes from Rev. 1? Well, the plate has a seam at the beginning of the extension of each leg and the finish on the inner side has been modified. Other than that, everything else is one hundred percent identical, and you can interchange parts between models since the turn of the last decade without issues.

Two color-matched matte black mounting bars are included for attaching the heatsink to the motherboard. First, put the plastic spacers on to each integrated bolt. The user then has the choice of either aligning the mounting bars according to the final desired orientation of the cooler, as the NH-D15 can be installed either horizontally or vertically. Our photo above shows the alignment of the mounting bars for a standard horizontal installation. Tighten the color-matched matte black screw caps over the bolts, and you are good to go. It is nice to see all the mounting hardware are color-matched to matte black, even though you cannot really see it once installed. The attention to detail is impressive.

Fastening the heatsink over the CPU socket proves to be a simple job after I applied some NT-H1 over my CPU. Remove the center fan to gain access to the spring loaded screw located on the NH-D15 heatsink itself. Align the heatsink with the screw threads on the mounting bars, and tighten the screws alternately until they stop. Overall, installation is straightforward, and Noctua's mounting system is very secure and distributes weight very well even though the heatsink is big and heavy.

The NH-D15 in single fan configuration mode will not interfere with your RAM like many modern heatsinks thanks to the high clearance fins. If you choose to install the included second NF-A15 HS-PWM, you may start to have issues. As I have mentioned earlier, it will definitely interfere with your memory no matter what profile it is. Therefore, you will need to mount the fan a little higher to accommodate the difference. As such, make sure your chassis is wide enough to accommodate the offset fan. Cases like the Fractal Design Define 7 and NZXT H710i will have more than enough room for clearance, but older models may not be wide enough.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware; Installation
3. Test Results
4. Conclusion