Page 2 - Physical Look - Hardware
The predecessor of today's cooler, the Dark Rock Pro 5, was a sleek-looking cooler with a top cover to hide the exposed heat pipe ends and aluminum fin. As such, it is no surprise we have a similar formula with the Dark Rock Pro 6, but there are some differences. Like the second book in the Lord of the Rings trilogy, there are two towers of fin stacks. A plastic top covers the two stacks. Instead of the more perforated look, this is a solid panel with the primary visual change of the manufacturer's logo smack in the middle. It aligns with the front fan to make for a cohesive unit, even if it still is notably separate. The middle there is a brushed silver area with the be quiet! logo in silver that shines and contrasts well. The only other be quiet! markings are found on the hub of the fan. I think this new iteration of their coolers is quite streamlined in design.
The be quiet! Dark Rock Pro 6's dimensions are 147mm in length, 140mm in width, and 169mm in height with the fans attached at the lowest position. These are typical dimensions for a cooler with 135mm and 120mm fans. Based on the placement of the heatsink fins and pipes, the Dark Rock Pro 6 is asymmetrical, with a thinner set of front leading fins and slightly more recessed compared to the back tower of fins. This is designed to reduce the overhanging portion of the Dark Rock Pro 6 over the memory slots. However, it is clear the front fan sits over most of the memory when installed. There is approximately 4.2cm of space between the lowest fin and the bottom of the base. The fan in default position sits higher up, increasing the clearance to 4.8cm here. You could raise the fan slightly higher too if you run into memory clearance issues, but this will also increase the overall height of the CPU cooler. My low-profile memory does not run into clearance issues, but it is possible yours may.
From the base where the metal contacts the processor, seven continuous U-shaped heat pipes lead away from the contact plate and split into two stacks of fins. This effectively makes fourteen heat pipes in total. The 6mm diameter heat pipes lead the heat away from the source due to low heat of vaporization, or phase change energy, of the fluid inside. They are aligned in a manner to spread out the heat in the array of radiating fins. There is a total of forty-five fins in each stack of varying sizes. Each fin is separated by a gap of about 2.5mm. In total surface area, I calculated it to be around 0.98m2 with some rough estimates. In total, this weighs about 1344g with both fans attached, or 875g for the heatsink alone. All these aspects are favorable for the be quiet! Dark Rock Pro 6 in terms of heat dissipation, but we will validate this in our performance tests.
There are two fans here, with a 120mm leading fan and a 135mm fan in the middle. These fans are made specific for the manufacturer's heatsinks, but they are based off the same Silent Wings designs we have seen before. You can see this through the ridged edges on each fan blade. Internally, both fans use fluid dynamic bearings with a 6-pole fan motor controlled by a PWM signal. In specifications, the 120mm fan has a maximum speed of 2000RPM and produces a maximum airflow and air pressure of 52.94CFM and 2.5mmH2O. The 135mm fan has a maximum speed of 1900RPM and produces maximum airflow and air pressure numbers of 79.48CFM and 2.25mmH2O. Together, be quiet! says the fans produce an overall noise level of 32.4dBA. The front fan attaches to plastic rails to let users slightly modify the height. The middle fan is attached to the middle topper plastic portion. As such, neither of these fans are user replaceable should they fail after an extended period of use. Thankfully, this should not happen for a while given the MTTF of 300,000 hours, or over 34 years.
One thing to note is the be quiet! Dark Rock Pro 6 has a built-in speed controller, which is why there is a custom header to connect the two fans together. On the middle cover at the back, there is a switch that is marked P and Q. This lets users toggle between performance and quiet modes, which have two different fan curves. In quiet mode, this turns off the fans under a 40% PWM signal. However, at full load, the two curves match up, which means this only reduces noise when there is less load, while kicking the fans to full gear when needed.
The base of the be quiet! Dark Rock Pro 6 is where you will see how the heat pipes lead out of the base and into the two fin arrays. The base itself is very flat with circular milling marks. This should result in even pressure applied across the top of the processor. The base and heat pipes are composed of copper. Copper is used because it has excellent heat transfer characteristics with a thermal conductivity of 401W/mK. The fins are an aluminum alloy, which is quite a bit lighter than copper. This reduction in weight will reduce stress on the motherboard, although aluminum has a lower conductivity of 237W/mK. This might not be optimal for heat transfer, but the trade-off is understandable.
On the outside, the copper base is concealed with an electroplated nickel. While nickel has a lower conductivity at 90.9W/mK, the layer is thin and should not adversely affect the performance to a signification degree. Furthermore, nickel and nickel-based alloys are used for their ability to withstand corrosion, even in higher temperatures. The reason nickel has these properties is because of its ductility and toughness up to its melting point of 1455c, measured at non-standard pressure. Its face-centered cube crystal structure is highly resistant to corrosion, which means we would not have corroded material built up on the surface. As a result, the be quiet! Dark Rock Pro 6 will not lose its cooling performance over time compared to a heatsink with a corroded copper surface.
All the heat pipes are soldered to the base, but the fins are pressed to the heat pipes. Pressed fins are typical but can lead to degradation over time as contact between metals may change due to thermal expansion and contraption. This also means fins can slide about and affect the gaps between each fin, especially at the bottom and top of the stacks. Even so, everything is well put together on the be quiet! Dark Rock Pro 6. The uniform black color finish makes everything look consistent despite the differences in materials.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Installation and Test Results
4. Conclusion
