Page 2 - Physical Look - Hardware
This is the top three-quarter view of the Noctua NH-D15 G2 HBC. This heatsink is an upgraded version of the Noctua NH-D15S, which is the offset version of the NH-D15 -- it is absolutely crazy how the original came out a whole decade ago. I really wish there is a chromax.black version though, which, unfortunately, has not been released yet at press time.
As far as engineering and implementation goes, fans can be mounted on using two clips each. Two Noctua NF-A14x25r G2 fans are included out of the box. Both of them are pre-installed out of the box, but you will need to take the pre-installed fans off for installation. These wire clips are easy to attach and remove in a uniform fashion. Integrated rubber dampeners on the included Noctua NF-A14x25r G2 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 G2 HBC 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. This is important for heat dissipation, since the cost is only a negligible decrease in heatsink surface area. There are 51 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, but denser than the standard NH-D15, since there are thirteen extra full-size plates on each tower. From my calculations, the total surface area of all the cooling fins combined is approximately 1.42m², which is up 0.22m² compared to the regular NH-D15.
The Noctua logo and branding is engraved horizontally on the larger top fin. The company specifies the NH-D15 G2 HBC at 1180g with no fans installed. With one stock fan attached, it will tip the scale at 1353g. Adding a second fan will increase the weight to 1525g. This is a hefty unit, and a heavy heatsink will stress your motherboard more than a lighter heatsink, but the effect can be 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 G2 HBC in just a short moment.
The Noctua NF-A14x25r G2 fan is very easy to dismount from the radiator. I do not see how anyone will want to replace the Noctua NF-A14x25r G2 with a different fan, but it still needs to be removed during installation. The Noctua NF-A14x25r G2 is an upgraded version of the NF-A14. Changes include what Noctua refers to as the Progressive Bend impeller, Centrifugal Turbulator hub, and addition of winglets. 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 older designs.
Those who are familiar with the lineup will know the Noctua NH-D15 G2 HBC is a mega-sized heatsink. Eight continuous U-shaped heatpipes lead away from the CPU contact base in two opposing directions for fourteen effective heatpipes, up from the previous six continuous U-shaped heatpipes design. 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 the fluid inside. The heatpipes are aligned in a linear manner, other than the outside two, to evenly distribute the heat in the radiating fins.
The Noctua NH-D15 G2 HBC comes at the cost of physical size. its height of 168mm 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 127mm. Add an extra fan to the front, and this figure jumps to 152mm. That said, with 1.42m² of surface area, combined Noctua's excellent NF-A14x25r G2 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 5.5cm between the heatsink contact base and the bottom of the upper fin array. This is the area where the NH-D15 G2 HBC 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-A14x25r G2 fan in front of the first radiator, all this clearance room will be no longer. The second NF-A14x25r G2 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 G2 HBC 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 G2 HBC CPU heatsink. The photo above shows the configuration of the heatpipes more clearly in relation to the base leading into the fin array. The fin stack is offset abut 1.5cm in relation to the base, so it is biased towards the upper edge of the motherboard to prevent interference with the first expansion slot. The contact base of the Noctua NH-D15 G2 HBC has a clean finish for optimal performance. Unique to the HBC, or High Base Convexity, variant of the Noctua NH-D15 G2 series is a curved base designed specifically for LGA 1700 CPUs' concave integrated heatspreader. Relatively flat CPUs such as AMD AM5 models can use the Low Base Convexity, or LBC, version. Anything else can use the standard NH-D15 G2.
Like all Noctua heatsinks we have reviewed in the past, the NH-D15 G2 HBC is a copper and aluminum hybrid heatsink electroplated with nickel. The vital parts such as the base and heatpipes are built using copper for the 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 G2 HBC from Noctua has none of the copper color with its copper heatpipes and base. Everything 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 G2 HBC 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 G2 HBC 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 G2 HBC 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.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Installation and Test Results
4. Conclusion
