be quiet! Dark Rock Pro 2 Review

Last time around we took a look at be quiet!’s top-down heatsink, the Shadow Rock TopFlow, which performed well, but had a few clearance issues. The Dark Rock Pro 2 is the next heatsink to go through testing. This heatsink uses the large dual-tower design that has become popular as of late for its performance. So, let’s dig in and see what else be quiet! has to bring to the US market!

Specifications & Features

(Courtesy of be quiet!)

Packaging & Accessories

The box looks pretty good, not gaudy at all. The front has a good picture of the cooler so consumers know what they’re buying, the name “Dark Rock Pro 2,” and the heat dissipation capacity of 220 W. The back of the box goes into more detail with the specifications table and a diagram with top and side views of the heatsink pointing out features. The sides of the box list some high points about the product in five different languages.

After opening the box, the accessories box rests on top of the well-padded Dark Rock Pro 2. No silica gel this time… The heatsink is protected by two pieces of foam, an L-shaped piece and a flat piece, which form a U shape around the heatsink.

The accessories include only what’s needed to mount the heatsink, such as instructions, brackets, screws, nuts, and a backplate.

Meet the Dark Rock Pro 2

Now we get to take a look at the Dark Rock Pro 2. It’s a rather large heatsink with a similar design of other dual-tower heatsinks, like the Thermalright Silver Arrow, Noctua NH-D14, and Phanteks PH-TC14PE.

I really like the brushed aluminum top-plate on the Dark Rock Pro 2. They could have rotated the “be quiet!” logo 90° to the right so that it would be right side up when looking into a case window. When looking at the heatsink from the bottom, we can see both towers have the same serrated and inward sloped fins that the Shadow Rock TopFlow used. The fans are installed on the serrated side of the fins from the factory.

On to the included fans. Interestingly enough, the Dark Rock Pro 2 uses two different fan sizes and speeds simultaneously. The outside fan is a 120×25 mm 1700 RPM BQT T12025-MF-PWM fan, and the inner fan is a 135×25 mm 1500 RPM BQT T13525-MF-PWM fan. Something unique about be quiet!’s fans is they don’t have the typical frame of other PC fans. The corners are just single flanges extruding from the center of the fan’s thickness. An obvious downside to this is that the mounting clips can’t be used to mount other fans, so some ingenuity will be needed to get different fans mounted on the Dark Rock Pro 2.

Installation

The first step in installation is to attach the brackets to the heatsink base. In my case, I’ll be using the LGA1155/1156 brackets. Each bracket uses two screws to hold it in place, as shown below.

Next, the backplate needs to be set up for attaching to the back of the motherboard. There are four screws that need the clear washers to put on them before putting the screws into the correct mounting holes on the backplate.

After the backplate is put in place, clip-on washers are attached to each screw to hold the backplate in place.

As with the Shadow Rock TopFlow, I found that turning the Dark Rock Pro 2 upside down and placing the motherboard on top was the easiest way to screw down the heatsink.

Potential Clearance Issues

There aren’t as many possible clearance issues with the Dark Rock Pro 2 as with the Shadow Rock TopFlow since it’s not as spread out . However, it does have the most dangerous clearance issue of the fan clips hitting the GPU’s PCB.

RAM

My Dominators, without their heatsinks, just did fit underneath the fan. So, RAM height clearance is right at 43 mm, but that shouldn’t be a problem to the majority of consumers. However, it is something to keep in mind.

GPU

The same clearance issue with GPUs in the top PCIe slot appears with the Dark Rock Pro 2, just as it did with the Shadow Rock TopFlow. The fan clips are touching the screws on the back of the GPU’s PCB, and the heatsink will most likely be installed in this orientation with the fans blowing right-to-left. It can be installed so the air is blowing from the top of the case down to the GPU, but that would counteract the front-to-back airflow of just about all cases out there.

Test Setup & Methodology

NOTE:  The large variance in temps in Ivy Bridge chips due to the TIM-to-IHS interface means that other i7 3770K CPUs could see much lower or much higher temps than my specific CPU.

Methodology

Cooling performance was tested as follows:

• Disabled all BIOS settings that cause the CPU clock speed and/or Vcore to fluctuate.
• Arctic Cooling MX2 thermal paste was used for consistency.
• Both included fans and Gentle Typhoon AP-15 fans were used for testing.
• Ambient temperature was measured with a Fluke 52 II at ~1 inch from the intake fan.
• Varied Vcore from 1.050 V to 1.400 V in 0.050 V increments to increase heat.
• 5-pass 2048 MB RAM LinX  runs at each Vcore interval were used to load the CPU.
• CoreTemp 1.0 RC4 was used to record minimum and maximum core temperatures.
• Stopped increasing Vcore once a core reached 90+ °C.

Sound level in dBA was measured 10 cm from the intake fan, and then estimated for other distances using the following formula:

L2 = L1 – 20 * log₁₀(r2/r1)

• L2 = dBA @ desired distance
• L1 = dBA @ reference distance
• r1 = reference distance
• r2 = desired distance

Why estimate sound level instead of measure at further distances? It’s because the meter I’m using is most accurate between 40-130 dBA, so I wanted to measure really close to the source to make sure I’m in that range to get the most accurate measurements.

Results

Cooling Performance

The competition for the Dark Rock Pro 2, in my testing, is the Prolimatech Genesis using two AP-15 fans. The Genesis is also a dual-tower heatsink, but with one tower parallel to the motherboard and one tower perpendicular to the motherboard. The Dark Rock Pro 2 falls behind the Prolimatech Genesis by ~3 °C on average when using the stock fans, and it’s behind by ~1.7 °C on average when using AP-15 fans. It’s also interesting that the Dark Rock Pro 2 only outperformed the Shadow Rock TopFlow by around 1 °C when both were using their stock fans. I expected a larger gap, but not sure if this is a testament to how good the Shadow Rock TopFlow performs or if the Dark Rock Pro 2 leaves something to be desired.

Rigging up two Gentle Typhoon AP-15 fans  made the Dark Rock Pro 2 perform better by 1-2 °C or so. However, there’s no way to easily mount the AP-15 fans on the Dark Rock Pro 2 because of how be quiet!’s fans are made, so actually trying to swap out the fans for such a small improvement probably isn’t worth the effort to most people.

As in the Shadow Rock TopFlow review, I was hoping to see more of an increased slope in some of the graphed data as Vcore increased, causing the data to spread out towards the end. That would show which heatsinks performed better at the higher heatloads.  However, the i7 3770K is a low power chip, so the heatsinks never seem to get overloaded past their rated TDP. When a heatsink gets overloaded, you’ll typically see a drastic increase in the slope of the graphed temperature data (Example from my Thermalright Shaman review). I look for something like that example in my testing, although not as pronounced for CPUs, to really show which heatsinks are better.

Sound Level

As mentioned before, sound level in dBA was measured at 10 cm (~4″) from the intake fan, then estimated for further distances 1-5 feet. Also, remember that this measurement was done using an open bench, not in a typical enclosed case. So, if a case is used, then expect to see lower dBA numbers than recorded below. According to the the rated 26.4 dBA at 100% in the specifications table, it looks like be quiet! tested sound level at a distance of around 3 feet and/or used an enclosed case when recording.

The Dark Rock Pro 2 is in the middle of the pack as far as sound level is concerned, being measured at 46 dBA at 10 cm when using the stock fans. Really, all the coolers tested are quiet from a normal distance of around 3 feet, and they will be even quieter when a case is used.

Conclusion

The Dark Rock Pro 2 is a large dual-tower heatsink in the same class as the NH-D14, Silver Arrow, Genesis, and PH-TC14PE. In my tests, it outperforms all the top-down coolers as expected, but it falls behind the Genesis by ~3 °C on average. Surprisingly, the Dark Rock Pro 2 barely outperforms the Shadow Rock TopFlow by around 1 °C on average, even though it’s much larger and costs almost twice as much. I think this just shows how well the Shadow Rock performs and not that the Dark Rock Pro 2 under-performs, since there isn’t a huge difference between the Dark Rock Pro 2 and the Genesis. As for sound level, the Dark Rock Pro 2 using its stock fan is one of the quieter heatsinks tested. It produces 30 dBA or less of noise at 100% fan speed at typical distances of 2-3 feet, and I wouldn’t expect anything less from a company called be quiet!.

The Dark Rock Pro 2 has a couple of downsides. The major con is that it ends up having the same, if not worse, clearance issue with the fan clips hitting the GPU as the Shadow Rock TopFlow experienced. This can be avoided by installing the heatsink so air blows top-to-bottom instead of right-to-left, but that would disrupt the majority of consumers’ case airflow. The clips could also be wrapped in something like electrical tape to prevent possible shorting. The minor downside is the fan’s frame requires the fan clips to be made such that other typical 25 mm thick fans cannot be installed easily. This is an issue resulting from how be quiet! makes their fans, so any heatsink using their fans will have trouble mounting different fans.

be quiet!’s products aren’t available in the US yet, but the MSRP is $95.00 for the Dark Rock Pro 2. I think $95.00 may be a little high for its performance since that places it up there with the highest of high-end air cooling heatsinks. Unfortunately, I didn’t have access to all the high-end heatsinks for testing for direct comparison.

Overall, the Dark Rock Pro 2 cools well with minimum noise and looks great. However, there may be better performance per dollar options out there that don’t have potential clearance issues with top PCIe cards.

Click the Approved stamp for an explanation of what it means.

– Matt T. Green (MattNo5ss)