Noctua NH-D15 G2 – Meeting all our expectations?

Key features

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Build, design and key features

Already at first glance, the Noctua NH-D15 G2 is a truly impressive cooler and leaves no one in doubt that it is the top of the class in premium air coolers. The basic design principle is of course the same as the vast majority of other air coolers, but as always, the execution and optimization of this concept matters as well. The development of this cooler has taken a very long time, so there are many optimizations and improvements right away.

   

But let’s start with the basics. The passive part of the cooler is made up of two very dense bundles of aluminium fins, which are soldered to eight copper heatpipes. Compared to the original NH-D15 version, the number of fins has been increased by 23, while the height and width of the cooler have been maintained. Overall, this is an increase in total fin surface area by a not insignificant 20% while reducing the depth of the cooler by 9 mm. In addition, the cooler is available in three different variants, which differ in the curvature of the cold plate. In today’s article, we are testing the standard version (also due to the test build with an LGA 1200 socket), but there are also HBC (High Base Convexity) and LBC (Low Base Convexity) variants available, which are designed for different types of processors according to the curvature of their heat spreaders. To avoid drowning in details here, I’ll refer you to an overview article directly from Noctua.

Both fin bundles include a cut-out on the outer edge to increase the compatibility of the cooler with various elements on motherboards, by which I mean especially the tall aluminum coolers of power deliveries and memory modules. At first glance, the design of this cooler may seem symmetrical, but appearances are deceiving. In fact, the front tower is 5 mm slimmer than the rear tower.

   

The top of the cooler is not covered by any decorative cover on the ends of the heatpipes and the manufacturer’s logo is stamped in the top fin of the rear tower. The large cold plate may appear to be a smooth surface at first glance, but upon closer inspection you will find microscopic grooves to optimize the distribution of thermal paste between the CPU heat spreader and the cooler’s cold plate.

   

In the photos above you can see the potential problem if for some reason you decide to place one of the fans behind the rear tower of the cooler. On most motherboards, you will need to place this fan in a higher position, reducing the overall efficiency of the cooler, and you may also run into compatibility issues with your case if you exceed the maximum allowable height for the CPU cooler with this maneuver. So if you have too tall RAM modules, for example, it might be better to fit the front tower with an NF-A12x25 fan. I also tested this combination out of curiosity, and the only problem was attaching the 120mm fan to the cooler, as the new clips could not be physically attached to this fan. So I replaced them with a pair of clips from the original D15 version, which turned out to be a problem-free solution. The results of this asymmetrical combination can be found in the relevant chapter, along with the results of the cooler with a single 140mm fan in the middle, should you for some reason decide not to use the front fan. The fan in the middle of the cooler, on the other hand, can be positioned slightly lower than the bottom fins, allowing you to effectively cool an aluminum heatsink of a VRM cascade on the motherboard and indirectly improving airflow around the RAM modules as well.

In the next photos you can see a detail of the bottom part of the cooler. It is clearly visible that the cooler is not symmetrical even in this level. This is for the sake of higher compatibility with the PCI Express slots on the motherboard. This is virtually the same design element as was used in the NH-D15S cooler. It can also be seen that the increase in the number of heatpipes results in the bottom of the cooler covering only five of the eight heatpipes, but this should have no impact on the resulting efficiency. The photo on the right then shows the cooler mounted on a motherboard to give you a clear idea of what the relationship between the cooler and the top VRM heatsink looks like. You may notice that the edge of the motherboard is virtually flush with the edge of the cooler, which in some cases could present a potential conflict with fans in the upper positions. It is therefore important to be aware of this fact.

   

I will gladly leave the detailed analysis of the new fans to my colleague Samák, but I will just stop at a few interesting details. The inclination and shape of the blades aims at optimizing the airflow through the fan with respect to the relative position of a blade part to the fan center, because the peripheral parts of the blades logically move faster than its central parts. These fans also use a new type of motor (NE-FD6) that uses, among other things, the Hall effect. The result is very quiet operation and lower power consumption with higher motor efficiency than previous versions (Noctua refers to this as etaPERF). Another interesting detail is the fact that the supplied fans are not exactly identical, but differ in the value of their maximum speed. The PPA variant reaches 1475 RPM, while the PPB variant maxes out at 1525 RPM. This difference of 50 RPM serves to reduce the risk of acoustic interference between the fans.

   

The contents of the Noctua NH-D15 G2 cooler package are plentiful and varied. The SecuFirm2+ mounting system has been around for some time now on Noctua industrial versions of coolers and we also saw it on the NH-P1 passive cooler. It differs from the previous SecuFirm2 version in that it does not use Phillips PH2 but Torx T20 screw heads, which increases the reliability of the cooler installation. Also, it reduces the wear on the grooves in the screw head. Of course, there is also the obligatory long shank screwdriver, this time in a full-blooded version with a rubberized handle. You’ll also find a fan splitter in the package, along with a pair of two adapters to reduce the maximum speed by 20%.

   

Owners of AMD AM5 processors will be pleased with the possibility of installing the cooler 7 mm off-center of the heat spreader for maximum efficiency, and they will also be pleased with the included plastic frame to prevent paste from running between parts of the articulated IHS. Owners of Intel LGA 1700 processors can take advantage of the 1 mm tall plastic washer under the processor’s socket mounting mechanism (ILM) to prevent excessive deformation of the processor substrate due to the pressure of the retention frame and thus worsening of the contact with the cooler. The included tube of NT-H2 paste is one of the best on the market, and in addition to this tube, you will also find one wet wipe in the package for perfect cleaning of the processor surface before applying the paste and installing the cooler. All topped off with a clear user manual and a metal sticker with the Noctua logo. A very rich and varied set of accessories, where nothing is really missing and, on the contrary, will only confirm to you that the NH-D15 G2 is simply a top-notch cooler where no expense has been spared.

Cooler and fan parameters

One of the characteristic features of high-end air coolers is their considerable size. With an overall height of 168 mm, you’ll need to be very careful when choosing a suitable case. Additionally, if the need arises to move the front fan to a higher position due to tall RAM modules, the overall height of the cooler can easily exceed 170 mm. However, for memory modules up to 32 mm in height, you can leave the front fan in its default position. What you won’t be happy about is the price tag of 150 EUR, which is already a lot of money for an air cooler. The NH-D15 G2 has a tough task of justifying this high price tag in front of it.

Along with the new cooler, brand new 140mm fans were also introduced. The NF-A14x25r expands Noctua’s portfolio of fans that utilize Sterrox LCP material for maximum impeller blade and fan frame stiffness. This allows the edges of the fan blades to be brought to within seven tenths of a millimeter of the frame edge, which increases the overall efficiency of the fan as evidenced by the specifications below. These fans will certainly be tested in great detail by Ľubo Samák, so keep an eye on our website for updates so you don’t miss anything.

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Testing methodology

As a test processor and heat generator I use the Intel Core i7-11700K on the Asus TUF Gaming Z590-Plus WIFI motherboard. I always use the thermal paste that comes in the package because it is also part of the equation for the efficiency of the cooler. So each cooler is tested as supplied by the manufacturer. The entire build is mounted on a Streacom BC1 frame with no fans to provide airflow. Acoustic shielding (acoustic foam on OSB boards) is installed around the test rig to eliminate ambient noise. The Voltcraft SL-100 calibrated noise meter is placed perpendicular to the cooler in a fixed position relative to the motherboard at a distance of approximately 35 cm from the processor socket.

   

Stress tests are performed using Prime95 with a duration of 30–35 minutes. Coolers are tested at four standardized noise levels (39, 42, 45 and 48 dBA) and at maximum speed. I did not measure the data for the 45 and 48 dBA noise levels initially, they were only incorporated into the methodology later. Because of this, results for these noise levels are only available for some (usually newer) coolers. The tests are run in two sets corresponding to the thermal output of the processor.

The first set of tests is at 125 W, the forced PL1 limit of the processor. The second set is then at a power draw of about 210 W (4500 MHz at 1.285 V). However, this level represents a very high heat concentration given the overall small die area. Thus, not all coolers can be expected to pass this set of tests at all noise levels.

The highest temperature reached is always recorded after the test. All data regarding temperatures and thermal output of the processor are obtained from HWiNFO64. The measured values are then adjusted against the temperature in the room as the resulting Delta T. The test success limit is set to 75 °C. Any higher value means a risk of processor temperature above 95–100 °C and a risk of thermal throttling. Therefore, if the cooler does not pass the load with a Delta T value below 75 °C, such a test is marked as a failure.

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Results – 39 dBA

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Results – 42 dBA

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Results – 45 dBA

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Results – 48 dBA

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Results – maximum speed

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Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Spectral analysis of noise

A spectral analysis of the noise cannot be missing either. This is a simple analysis at noise levels of 39 dBA, 45 dBA and at maximum speed of the cooler. For the analysis I use the UMIK-1 microphone from miniDPS in conjunction with True Audio’s TrueRTA application. The resolution of the analysis is 1/24 of an octave and the shape of the spectrogram is an average of 100 samples acquired over 20–30 seconds.

Well, the time has finally come this year, as a few weeks ago Noctua introduced the long-awaited NH-D15 G2 cooler, which has seen years of development, optimizations, and delays. Expectations are so extremely high and I myself am curious if we will see a new king among coolers. A really interesting battle awaits us, because in the meantime, several high-end coolers have appeared on the market, which the NH-D15 G2 will have to beat.

Conclusion and evaluation

The Noctua NH-D15 G2 is a really impressive cooler with a clearly visible improvement over the previous version that has been on the market for a decade. The efficiency of this cooler is very high indeed and the acoustic performance outside of the highest speeds is very refined. The only minor shortcoming is the low pitched humming resonance at around 1200 RPM. The workmanship is traditionally perfect, including the improved mounting system, which is now truly second to none. The supplied accessories are also very plentiful and more than fully reflect what belongs to any high-end cooler. All topped off with a six-year warranty.

Probably the only, but unfortunately not insignificant problem of this cooler is its very high price, especially considering its competition, which has definitely not slackened over the years. The Noctua NH-D15 G2 cooler practically only matches its rivals without surpassing them in any significant way and thus is not able to offer a similarly interesting price/performance ratio. Thus, it takes home the Approved editorial award without the slightest objection, but unfortunately I cannot award it the Top Notch one in good conscience.

English translation and edit by Jozef Dudáš

• Contents
• Key features
• Measurement methodology
• Results – 39 dBA
• Results – 42 dBA
• Results – 45 dBA
• Results – 48 dBA
• Results – maximum speed
• Spectral analysis of noise
• Conclusion and evaluation