be quiet! Dark Power Pro 10 850 W Power Supply Review
By Gabriel Torres on July 16, 2012


Introduction

Hardware Secrets Silver Award

The German brand be quiet! released last month a new high-end power supply series, the Dark Power Pro 10, with models ranging from 550 W to 1,200 W. The 850 W model has the coveted 80 Plus Platinum certification, while all other models have the 80 Plus Gold certification. Let’s test the 850 W version and see if it is a good pick.

The 550 W, 650 W, and 750 W models are manufactured by FSP, while the 850 W, 1,000 W, and 1,200 W are manufactured by Seasonic.


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Figure 1: be quiet! Dark Power Pro 10 850 W power supply

be quiet! Dark Power Pro 10 850w
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Figure 2: be quiet! Dark Power Pro 10 850 W power supply

The be quiet! Dark Power Pro 10 850 W is 7.3” (186 mm) deep, using a 135 mm fluid-dynamic bearing fan on its bottom (be quiet! BQT T13525-XF20, a.k.a. “Silent Wings P10”).

The reviewed power supply has a modular cabling system with 15 connectors: four for video card power cables, five for peripheral/SATA cables, one for the ATX12V/EPS12V cable, four for fan power cables, and one for the “overclocking” panel, which is used for selecting whether the power supply will use a multiple +12 V rail or a single +12 V rail configuration. Only the main motherboard cable is permanently connected to the power supply. This power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge. The number of connectors available is impressive. It allows you to install, out of the box, three high-end video cards that require two auxiliary power connectors each. Another highlight of the cable configuration is the presence of cables with lots of connectors as well as cables with a single connector. This way, you can install only the cables you are going to actually use, preventing your computer from ending up with a lot of unused cables hanging inside. For example, if you have only one hard drive, you can install the cable that has only one SATA power connector. On competing products, you would have to use a cable where two or three connectors would be left unused, occupying space inside the case.

Another highlight of the Dark Power Pro 10 850 W is the presence of four cables for powering fans. This way, you can have at least some of the fans available on your case controlled by the temperature sensor available inside the power supply.

The reviewed power supply comes with a switch for you to select your favorite configuration for the +12 V output: single-rail (with the switch turned on) or multiple-rail (the default configuration). The unit also comes with a jumper in case you want to “permanently” configure the unit as single-rail but don’t want to install the switch.

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Figure 3: Cables

be quiet! Dark Power Pro 10 850w
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Figure 4: Single-rail/multiple-rail switch

Let’s now take an in-depth look inside this power supply.

A Look Inside the be quiet! Dark Power Pro 10 850 W

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

be quiet! Dark Power Pro 10 850w
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Figure 5: Top view

be quiet! Dark Power Pro 10 850w
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Figure 6: Front quarter view

be quiet! Dark Power Pro 10 850w
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Figure 7: Rear quarter view

be quiet! Dark Power Pro 10 850w
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Figure 8: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil. 

In the transient filtering stage, this power supply is flawless, with two Y capacitors more than the minimum required. The metallic piece you see in Figure 9 is a complete filtering circuit.

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Figure 9: Transient filtering stage (part 1)

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Figure 10: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the be quiet! Dark Power Pro 10 850 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the be quiet! Dark Power Pro 10 850 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBJ2506 rectifying bridges connected in parallel and attached to an individual heatsink. This bridge supports up to 25 A at 100° C. So, in theory, you would be able to pull up to 5,750 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 4,600 W without burning themselves out (or 5,175 W at 90% efficiency). Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

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Figure 11: Rectifying bridges

The active PFC circuit uses two IPW60R125P MOSFETs, each supporting up to 25 A at 25° C or 16 A at 100° C in continuous mode (see the difference temperature makes) or 82 A at 25° C in pulse mode. These transistors present a maximum 125 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

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Figure 12: Active PFC diode and active PFC transistors

The active PFC circuit is controlled by an NCP1654 integrated circuit.

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Figure 13: Active PFC controller

The output of the active PFC circuit is filtered by two 390 µF x 420 V Japanese electrolytic capacitors, from Chemi-Con, labeled at 105° C and connected in parallel. This is the equivalent of a single 580 µF x 450 V capacitor.

In the switching section, four IPP60R199CP MOSFETs are employed using a resonant configuration. Each transistor supports up to 16 A at 25° C or 10 A at 100° C in continuous mode or up to 51 A at 25° in pulse mode, with a maximum RDS(on) of 199 mΩ.

be quiet! Dark Power Pro 10 850w
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Figure 14: The switching transistors

The switching transistors are controlled by a CM6901 integrated circuit.

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Figure 15: Resonant controller

Let’s now take a look at the secondary of this power supply.

Secondary Analysis

The be quiet! Dark Power Pro 10 850 W uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Also, the +12 V output uses a synchronous design, where the rectifiers were replaced with MOSFETs. Both designs are used to increase efficiency.

The +12 V output uses four BSC018N04LS G MOSFETs, each supporting up to 100 A at 100° C in continuous mode or 400 A at 25° C in pulse mode, with a maximum RDS(on) of 1.8 mΩ. These transistors are located on the solder side of the printed circuit board, using the power supply case as a heatsink.

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Figure 16: The +12 V MOSFETs

The DC-DC converters are located on the same printed circuit board as the modular cabling system. Both are managed by an APW7159 PWM controller, with each output using three RJK0332DPB MOSFETs, each supporting up to 35 A at 25° C in continuous mode or 140 A at 25° C in pulse mode, with a maximum RDS(on) of 8.5 mΩ.

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Figure 17: The DC-DC converter

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Figure 18: The DC-DC converter

This power supply uses a PS232F monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections. There are four +12 V over current protection (OCP) channels, matching the number of +12 V rails advertised by the manufacturer.

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Figure 19: Monitoring circuit

The electrolytic capacitors that filter the outputs are also Japanese, from Chemi-Con, and labeled at 105° C, as usual. This unit also makes use of solid capacitors.

Power Distribution

In Figure 20, you can see the power supply label containing all the power specs.

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Figure 20: Power supply label

This power supply is advertised as having four +12 V rails, which is correct, since the monitoring integrated circuit has four +12 V over current protection (OCP) channels. Click here to understand more about this subject. Optionally, you can configure this power supply to use a single +12 V rail by installing the switch shown in Figure 4.

The four +12 V rails are distributed as follows:

This distribution is perfect. However, when using two connectors for video cards on the power supply (i.e., when you install four video cards, since each connector has two cables), don’t install them side-by-side, or they will be connected to the same rail; skip one connector (i.e., use the first and the third connectors) to make each video card use a separate rail. Of course, if you configure the power supply to use a single-rail configuration, what we are saying won’t matter.

How much power can this unit really deliver? Let’s find out.

Load Tests

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.” 

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, we configured the power supply to use a single +12 V rail design, so both inputs were connected to the power supply’s single +12 V rail. (We connected the EPS12V connector to the +12VB input.)

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

6 A (72 W)

13 A (156 W)

19 A (228 W)

25.5 A (306 W)

32 A (384 W)

+12VB

6 A (72 W)

13 A (156 W)

19 A (228 W)

25.5 A (306 W)

31.5 A (378 W)

+5 V

1 A (5 W)

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

+3.3 V

1 A (3.3 W)

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

+5VSB

1 A (5 W)

1.5 A (7.5 W)

2 A (10 W)

2.5 A (12.5 W)

3 A (15 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

163.6 W

341.9 W

503.6 W

675.7 W

848.8 W

% Max Load

19.2%

40.2%

59.2%

79.5%

99.9%

Room Temp.

45.5° C

45.0° C

45.1° C

46.7° C

49.4° C

PSU Temp.

46.5° C

46.6° C

47.0° C

48.0° C

49.8° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

181.9 W

374.0 W

554.5 W

754.0 W

963.0 W

Efficiency

89.9%

91.4%

90.8%

89.6%

88.1%

AC Voltage

113.9 V

111.9 V

109.3 V

107.4 V

105.1 V

Power Factor

0.994

0.995

0.997

0.998

0.998

Final Result

Pass

Pass

Pass

Pass

Pass

The 80 Plus Platinum certification guarantees minimum efficiencies of 90% at 20% load, 92% at 50% load, and 89% at 100% load. In our tests, the be quiet! Dark Power Pro 10 850 W presented 89.9% efficiency at 20% load, matching the 80 Plus Platinum certification. We didn’t test this power supply at 50% load, but considering that we saw 91.4% efficiency at 40% load, we can assume that this unit is able to achieve 92% efficiency at 50% load. At full load, we saw 88.1% efficiency, one percentage point below the minimum advertised by the 80 Plus Platinum certification. However, we have to consider that during this test, the AC voltage dropped to 105 V, which is probably the culprit. Also, always keep in mind that we test power supplies between 45° C and 50° C, while the 80 Plus tests are conducted at 23° C, and efficiency drops with temperature.

All positive voltages were closer to their nominal values during all tests (3% voltage regulation). The -12 V output, however, got outside this tighter regulation during tests one (-11.42 V) and two (-11.55 V), but were still inside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The be quiet! Dark Power Pro 10 850 W provided very low ripple and noise levels, as you can see below.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

19.2 mV

18.0 mV

20.4 mV

25.2 mV

30.6 mV

+12VB

19.8 mV

18.6 mV

19.2 mV

23.6 mV

28.4 mV

+5 V

8.2 mV

9.0 mV

9.4 mV

11.0 mV

13.2 mV

+3.3 V

10.4 mV

12.2 mV

13.8 mV

15.8 mV

17.8 mV

+5VSB

9.0 mV

11.0 mV

12.8 mV

14.8 mV

16.2 mV

-12 V

16.6 mV

17.2 mV

17.0 mV

17.8 mV

22.2 mV

Below you can see the waveforms of the outputs during test five.

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Figure 21: +12VA input from load tester during test five at 848.8 W (30.6 mV)

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Figure 22: +12VB input from load tester during test five at 848.8 W (28.4 mV)

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Figure 23: +5V rail during test five at 848.8 W (13.2 mV)

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Figure 24: +3.3 V rail during test five at 848.8 W (17.8 mV)

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit failed this test, since it burned while it was configured as described in the table below. This may mean that we got a defective sample, so we asked a second sample from the manufacturer, which should arrive shortly. So, do not hold this result against the manufacturer before we do test the second sample. During this test, noise and ripple levels increased a lot, showing that the unit was reaching its limits (85.6 mV at +12VA, 90.4 mV at +12VB, 30.2 mV at +5 V, and 46.0 mV at +3.3 V). All voltages were within 3% of their nominal values.

Input

Overload Test

+12VA

33 A (396 W)

+12VB

33 A (396 W)

+5 V

22 A (110 W)

+3.3 V

22 A (73.6 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

985.6 W

% Max Load

116.0%

Room Temp.

44.4° C

PSU Temp.

48.2° C

AC Power

1,142.0 W

Efficiency

86.3%

AC Voltage

104.2 V

Power Factor

NA

Main Specifications

The main specifications for the be quiet! Dark Power Pro 10 850 W power supply include:

Conclusions

It is very clear that be quiet! is trying, with the Dark Power Pro 10 series, to create the most flawless and complete PC power supply series available on the market today. The cable configuration of the 850 W is the most complete possible, allowing you to install three high-end video cards out of the box. The single/multiple rail switch puts an end to the endless discussion of which configuration is better: you simply choose which one you think is better. We really loved that this power supply comes with four cables for fans with two power connectors each; this way you can make all the fans available on your case to be temperature-controlled by the power supply.

Performance-wise, the Dark Power Pro 10 850 W presented high efficiency between 88.1% and 91.4%, a bit below the numbers promised by the 80 Plus Platinum certification, but the AC voltage at our lab was at 105 V instead of 115 V, which could have caused this. Noise and ripple levels were very low, and all positive voltages were within 3% of their nominal values.

The only problem we had with this unit was that it burned when we overloaded it to 985 W. This may mean that we got a defective sample, so we asked a second sample from the manufacturer, which should arrive shortly. So, do not hold this result against the manufacturer before we do test the second sample.

Technically, the Dark Power Pro 10 850 W is a good power supply, targeted to users who demand only “the best.” Its price, although high, is not bad for an 850 W unit with 80 Plus Platinum configuration and the number of extra features it brings.

Originally at http://www.hardwaresecrets.com/article/be-quiet-Dark-Power-Pro-10-850-W-Power-Supply-Review/1593


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