Business, Hardware, Reviews

BeQuiet! Dark Power Pro 750W Review – Whisper Quiet Yet Powerful

While Be Quiet! Has been a leading provider of power supplies in Germany for several years, now it aims to target the North American market with high quality products. The Dark Power Pro 10 series power supplies have been introduced to the North American market a few months ago and in this review we will take a closer look at one of these.

The Power Supply

The Dark Power Pro 10 series is available in models with 550W, 650W, 750W, 850W, 1000W and 1200W. All of those received the 80Plus Gold certification (except the 850W model which is even rated Platinum) and share a set of common features. Basically the difference lies in the output power and related to that the number of connectors that come with the PSU. BeQuiet! supplied us with the 750W model (BQT P10-750W) which we looked at in detail for this review.

The Dark Power Pro 10 lives up to it’s positioning as a high end product aimed at enthusiasts with a visually appealing design. This already starts with the packaging. Both the power supply and all the accessories are neatly packed. There is plenty of foam in the box that ensures the PSU and it’s accessories are not damaged by transport. The modular cables come in a neat box.

On the sides the company and product name as well as the power rating and 80Plus Gold certification is presented in a visually appealing fashion. A quick look at the power rating specifications shows that as we expect from a modern PSU, the majority of the peak power output can be consumed from the 12V rails. This is where the majority of the load occurs in a modern system. At the back side a honeycomb shaped fan-grill allows for both ample and quiet airflow to the components. At the bottom the 135mm SilentWings fan is situated. At the top the specifications can be found. The front and rear ends are coated with rubber in order to reduce vibrations.

According to the specifications, the PSU supports the following protection mechanisms:
– OCP (over current protection)
– UVP (under voltage protection)
– OVP (over voltage protection)
– SCP (short circuit protection)
– OTP (over temperature protection)
– OPP (over power protection)

The power supply would switch off when it reaches operating conditions without the relevant specifications and in some cases like OTP would only allow to be powered up again once safe operating conditions are reached again.

Modular Cables

Another high end feature the Dark Power Pro delivers on is modularity. Any connector except for the main ATX 20/24pin connector can be attached separately to the PSU. The cables including the main ATX connector are nicely sleeved.

The graphic from the datasheet details the cables that ship with the Dark Power Pro 750W:

Do note that not all of these cables can be connected to the PSU at the same time. This concerns mostly the P4/P8 ATX12V connectors and the single Molex- and SATA-Connectors. There is only one connector on the PSU for the P8/P4 connectors. Thus the PSU is able to either provide two P8 connectors (one of which is a P4 + P4 one), or a single P4 + P4 one or a single P4 one. The reason for this is that Be Quiet! wants you to be flexible. If you don’t need the maximum connectivity the PSU can deliver you can opt for a cable with lesser connectors to reduce clutter in the case.

The same applies to the single connector Molex and SATA connectors. While the PSU only has five connectors that allow you to plug in all the multi-connector Molex- and SATA-wires, if you don’t need them all you can swap out one or more of those for those single-connector cables to reduce cable clutter.

On the last pages of the manual one can also find recommendations and information about the 12V rails. The manual makes recommendations for dual- and quad-GPU systems regarding where to put the connector to which GPU to ensure even loading of the rails. It also details the pins of each connector and general information about which 12V rail is responsible for which connectors.

Fan Control

The Dark Power Pro series includes a fan control system that not only controls the integrated 135mm fan from beQuiet’s SilentWings line but also up to four of external fans according to the thermals measured in the PSU. This ensures quiet operation while at the same time reducing noise levels as much as possible.

The fan connectors are supposed to handle one fan per connection, even though each cable allows to connect a fan via the usual 3pin connector or a molex connector. In both cases the fan is dynamically regulated via voltages ranging from 4V to 12V. We tested this with a variety of 80mm and 120mm fans that get reliably controlled. The total load of all the connected fans should not exceed 0.8A at 12V, which shouldn’t be an issue with sane speeds. Coincidentally that is the maximum current four Silent Wings 2 140mm fans from beQuiet! would draw.

Overclocking Key

The Dark Power Pro series also come with a way to configure the PSU to operate in single 12V rail mode. To this end one can either plug in a jumper to set the PSU to single rail mode permanently or use the PCI bracket with the switch which allows to selectively turn on and off single rail mode. If the switch is turned on, the red LED lights up. The manual cautions that either the switch or the jumper should only be changed while the PSU is off.

Technically what this allows you to do is disable the separate OCP circuits for the four 12V rails. Instead OCP will kick in only when the total 12V budget ? 62A in the case of the 750W model we reviewed ? is used up and the current draw goes over the specified thresholds of OCP. In general it is not advisable to enable single-rail mode as this renders the protections of OCP virtually useless. However in some overclocking scenarios with very high draw on one of the rails it might be necessary to ensure system stability.


The Dark Power Pro 10 750W carries an 80 Plus Gold certification that requires the PSU to meet certain efficiency requirements at different load levels. Peak efficiency is required at 50% load, which would be 90% for 115V grids and 92% for 230V grids, whereas at the 20% and 100% load operatin
g points only 87% (115V) respectively 88% (230V) is required. Be Quiet! claims an efficiency level of up to 93%, but doesn’t specify at what grid voltage and what load level. If it refers to 230V operation at 50% load it would still be above the formal requirements.

While there exists sophisticated equipment to measure a PSU at different load levels to determine it’s efficiency and ultimately check for compliance with the certification, given the steep cost of such equipment we took a different approach for testing efficiency. We simply compared the power draw of a complete system while loading the CPU and or GPU with different power supplies. In the end this is what the end user would get when swapping one PSU for another with higher efficiency.

First the PSU was employed with our Richland test system as used in our review. Given this PSU has a sustained peak power output of 750W (after conversion loss), the APU system would only load it slightly above 20% in the worst case and would hover most of the time below the 20% mark where efficiency often drops off quickly. Nevertheless it was able to eek out a minor improvement over the Corsair TX650W.

To compare efficiency at different loading levels, we set up another test system consisting of an AMD FX-8350, Gigabyte 990FXA-UD3 motherboard, 2x 4GB DDR3-1600 RAM and a Radeon 7970 (non-GHz Edition at stock). We loaded up the system with 7 threads of Prime95 and Kombustor to get both the CPU and GPU fully stressed. Note that if we would use eight threads of Prime95, power consumption would drop due to the CPU not being able to feed the GPU quick enough, that’s why we left one core free just for feeding the GPU.

While such extreme load conditions would normally not occur, we simply chose to do it to put high stress on the power supplies. At this power draw the power supplies would be at a 70-80% load level here. Note that the Be Quiet! PSU would have a small advantage due to it’s higher peak power output. Still the test shows the difference a higher efficiency PSU can make.


Overall we were very pleased with the Dark Power Pro 10 750W power supply. It is a high quality high-end solution that left a good impression. Not only does it provide excellent power delivery, it also comes in a very appealing design. The modular cables provide plenty of connectivity and lots of flexibility. The availability of a switch to operate the PSU in single rail mode also provides flexibility, although we believe the vast majority of users shouldn’t use single rail operation due to the less effective OCP in this case.

Be Quiet! touts the ?legendary silence? of the product line, which aside from the marketing speech is no overstatement. Even under high load the PSU fan stays silent. On top of that the Dark Power Pro 10 also allows you to keep your case fans silent as well. The rubber-coated body also adds to an all-around quiet design.

The only thing that might make someone hesitate is the price tag which is high but given the exceptional quality and features it is justified. The PSU also comes with a five year warranty which means that this could be a lasting component in a PC build and also underlines the manufacturers confidence in the product. Therefore we can also confidently recommend the product, given our positive experiences with it.