be quiet! Dark Power 12 850W (Titanium) Review

1. Introduction2. Bundle & Cabling3. External4. Internal5. Testing Methodology and Results6. Closing Thoughts7. View All Pages

Today we are taking a look at one of the latest power supplies from be quiet! – specifically the 850 Watt version of the Dark Power 12. This unit is fully modular, and Titanium rated. be quiet! offer three versions in this range, a 750 watt, 850 watt and 1000 watt model.

be quiet! have had pretty good success with their high end power supplies over the years, relying on relationships with well known OEM partners to deliver quality products to the discerning enthusiast.

The topology of these latest units is based around an active rectifier with Full Bridge LLC + SR + DC-DC. This unit is equipped with five daughter cards that provide technologies such as active rectifier, active PFC, Full Bridge LLC and DC to DC transformation.

be quiet! have always focused on reducing noise within their power supplies and these units are supplied with a frameless fan, which rests in a funnel shaped opening. This unique fan is based on the award winning Silent Wings technology to keep noise levels to an absolute minimum.

be quiet! are quite confident with this design and are offering a 10 year warranty without any geographical restrictions. We will take a close look at the design later in the review.

The company sent us over the table above showing how the Dark Power 12 fits slots into the portfolio of be quiet! units. Their plan is for the Dark Power 12 to completely replace the Dark Power Pro 11 range.

Key points:

• 80 Plus Titanium certification
• Active Rectifier + Full Bridge LLC + SR + DC-DC
• be quiet! frameless Silent Wings fan
• Overclocking Key
• Modular cables and classic design
• Ready for Windows Modern standby mode

be quiet! artwork has remained consistent now for many years – I do like the black and orange accents, it's very effective. The front of the box showcases a high resolution image of the power supply along with key details such as efficiency.

Inside the main box, is a smaller box, containing the cables and accessories.

The primary cables are nicely finished and there is also a bunch of felt, and plastic cable ties to aid with routing during the build phase.

be quiet! also ship an ‘overclocking key' with the unit which switches the power supply between the factory default four rail setting to a high powered single rail mode.

This power supply is completely modular, which means you only need to attach the cables you need to use for your specific build configuration.

As we would expect, the power supply is true to the high standards of finish we expect from be quiet!. Paint is both deep and evenly finished and its a very colour neutral design aesthetic, meaning it will work within any schemed system build.

A large fan takes centerstage behind a mesh grill on one side of the unit and we will take a closer look at this shortly when we open the unit to look inside.

One end of the power supply is home to the modular bay, clearly labelled to ensure the build phase is kept simple and clean. The other end of the power supply has a power connector, switch and vented panel. The Overclocking key attaches to the port labelled ‘OCK' bottom right in the image above, top left.

The 850W power supply in this range is capable of delivering 70A across the 12V rail for a total of 840 watts. Enough for any single GPU based system today.

After removing the top of the power supply we can see the fan is sandwiched between two pieces of plastic. This ‘frameless' fan design was created by be quiet! to help reduce noise levels. The fan has been developed for use specifically in power supplies and is a unit adapted from the Silent Wings 3 range.

This fan has a six pole motor and fluid dynamic bearings to increase life span over a traditional fan design. The mesh cover on the actual power supply chassis is to help increase airflow while reducing unwanted turbulence.

The OEM of this unit looks to be FSP, as was the Straight Power 11 Platinum unit we reviewed last year. Clearly the relationship is working for be quiet! on some level. The topology of this power supply is an Active Rectifier + Full Bridge LLC + SR + DC/DC.

The design is quite clean inside with gold soldering throughout. They are using high grade 105c rated Nippon Chemi Con capacitors  (KMZ series) in the primary stage – rated 420V 470uF and 330uF for a total of 800uF.

This is a block diagram of this specific design. The Dark Power 12 has a bridge rectifier on the AC side utilising four N-Channel Super Junction MOSFETs, controlled by four controller ICs, called CMDRBR. This helps the supply to reach the lofty heights of Titanium efficiency. Full Bridge is the number of MOSFETs used in the PWM stage (no 4 in the block diagram above). The MOSFETs are responsible for creating high frequency alternating current, which gives high levels of efficiency for the main transformation.

The circuit following the Full Bridge topology is LLC. L is the switching symbol for a coil, the C for a capacitor. The LLC series resonant circuit consists of two induction coils (L1+L2) and one capacitor (C1).

This LLC circuit is responsible for smoothing out the alternating voltage. The Dark Power 12 is using both pulse width modulation and frequency modulation to adjust power transformation. Starting at around a load of 10 to 15 percent, the LLC circuit modifies the frequency, producing better results. The best results are obtained at low frequency and high load or vice versa.

Instead of generating all necessary voltages (3.3V, 5V and 12V) from the AC on the primary side, the lower 3.3V and 5V voltages are generated from the 12V DC after the main transformation.

The Dark Power 12 power supplies are incorporating five daughter cards. be quiet! claim that the ‘modular design allows for separate production and quality control of the different PCBs.'

The cleaner layout however will help increase airflow throughout which dissipates heat faster. This higher build density across the PCB helps reduce circuit paths, again helping efficiency while potentially reducing ripple/noise levels.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. We run at 35c in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We test in a single +12V configuration.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
85W	0.95	3.35	0.92	5.01	6.00	12.07	0.50	5.02	0.20	-12.02
170W	1.70	3.35	1.67	5.00	12.35	12.04	1.00	5.02	0.20	-12.02
425W	3.00	3.34	3.05	5.00	32.20	12.00	1.50	5.02	0.30	-12.01
640W	4.05	3.33	4.05	5.00	49.00	11.95	2.00	5.01	0.30	-12.01
850W	5.00	3.33	5.23	5.00	65.52	11.92	2.50	5.00	0.50	-12.01

Load regulation is very strong with the rails holding with 1.5% of recommended specifications.

be quiet! Dark Power 12 850W	Maximum Load
	934W

We managed to get the power supply to deliver 934W before it would shut down, delivering around 84W more than rated specifications.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
760W	1.0	3.35	1.0	5.00	60.0	11.95	0.2	-12.01	0.50	5.01
165W	15.0	3.31	18.0	4.97	2.0	12.06	0.2	-12.01	0.50	5.01

The power supply dealt with the demanding cross load test very well exhibiting little fluctuation. It was tasked with 60A on the +12V rail and it held at 11.95V. The other rails delivered solid results also.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
100W	5	5	10	5
225W	5	10	15	5
450W	5	15	20	5
675W	10	15	25	10
850W	10	15	30	15

Noise suppression is very good indeed with both the primary and minor rails exhibiting great all round results and well within industry rated parameters.

Efficiency (%) 240V
100W	92.7
225W	94.2
450W	95.8
675W	95.1
850W	94.2

As we would expect efficiency levels are very high across the range of loads – peaking at close to 96% and dropping to just over 94% at full load.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the power supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
100W	<28.0
225W	28.6
450W	32.4
675W	34.1
850W	35.8

We really do rate the be quiet! Silent Wings fans very highly and this shows that throughout the load range the fan noise emissions are well controlled – even at full load we wouldn’t call the fan too intrusive. The pitch is quite low, so it is not that noticeable, especially when you would have other fans running in a system build.

Temperature (c)
	Intake	Exhaust
100W	37	39
225W	38	42
450W	39	43
675W	43	48
850W	45	53

The large fan spins quite slowly at lower load levels due to the efficiency of the unit. Temperatures are well maintained throughout the full range of loads.

Maximum load	Efficiency
934 watts	93.7

At 934 watts, this unit managed to deliver efficiency at 93.7%.

The be quiet! Dark Power 12 power supply has proven itself capable in our tests today. It is a fitting design to slot in at the top of the be quiet! hierarchy.  There are three models in this specific range, a 750W, 850W and 1000W – priced at £205.99, £239.99 and £269.99 respectively.

Discussing pricing right now seems almost pointless as quick searches online show that there are very few, if any, Titanium power supplies actually available to buy. It has been a terrible 12 months for gamers wanting to upgrade their systems. Let's just hope that be quiet! can actually get some of these power supplies into the channel in the coming months, but based on what we are seeing it seems somewhat unlikely.

Technically this long running partnership with FSP is proving fruitful. There are no glaring issues we feel the need to raise. The power supply was able to deliver close to 950W before safely shutting down. Load regulation is solid across the board. Efficiency levels peak at around 96% dropping to just over 94% at full load.

The unit incorporates a custom version of the highly regarded Silent Wings fan. This frameless fan sits in a funnel shaped opening, enabling high levels of air circulation and the corresponding results are stellar. Noise levels are also basically inaudible under normal use.

The colour neutral design will ensure the supply can fit into any themed build without causing a visual distraction, while the fully modular design ensures that only required cables can be adopted into the build to maximise routing efficiency.

The overclocking key allows the enthusiast user to switch between multi and single rail operation and the 10 year warranty gives peace of mind to a prospective customer.

Pros:

• High efficiency levels.
• Visually attractive.
• Fully modular.
• Custom Silent Wings fan is quiet.
• 105c rated Japanese capacitors in primary stage.
• Overclocking key may prove useful for some systems.
• colour neutral for themed build.

Cons:

• Finding one in stock in the first half of 2021 will likely be an issue.

Kitguru says: The be quiet! Dark Power 12 850W has proven to be a great performer in our tests. Load regulation, efficiency and ripple suppression are all stellar, and if you can can manage to find one in stock via your favourite etailer, then we have no hesitation in recommending it for a new system build.

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