BeQuiet Dark Power Pro 10 850W PSU Review

1. Introduction2. BeQuiet Dark Power Pro P10 850W (Bundle & Cables)3. BeQuiet Dark Power Pro P10 850W (External)4. BeQuiet Dark Power Pro P10 850W (Internal)5. BeQuiet Dark Power Pro P10 850W (Super High Res Gallery)6. Testing Methodology & Results7. Closing Thoughts8. View All Pages

Additional technical assistance: Peter McFarland and Jeremy Price.

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. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 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

12V output is combined for our testing.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
100W	1.52	3.38	1.75	5.07	6.67	12.14	0.50	5.05	0.20	-12.03
225W	3.75	3.36	3.82	5.04	15.58	12.12	1.00	5.04	0.20	-12.05
450W	7.51	3.35	8.34	5.03	30.82	12.09	1.50	5.02	0.30	-12.07
675W	11.31	3.32	12.30	5.02	47.51	12.07	2.00	5.01	0.50	-12.10
850W	1.48	3.29	1.13	5.00	63.50	12.03	0.50	5.00	0.20	-12.11

Load regulation is fantastic, holding well on all rails, even at full load.

BeQuiet Dark Power Pro 10 850W	Maximum Load
	933W

We managed to get the PSU to achieve 933W before it would shut down, delivering around 83W more than the 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	3.37	1.0	5.06	60.0	12.02	0.2	-12.04	0.50	5.03
165W	15.0	3.31	18.0	5.02	2.0	12.13	0.2	-12.02	0.50	5.01

The power supply is well designed to cope with demanding situations. It was tasked with 60A on the +12V rail and it held at 12.02V. The other rails were equally as impressive.

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	5	15	5
450W	5	10	20	5
675W	10	10	25	10
850W	10	15	30	10

Noise suppression results are superb, peaking at 30 mV on the +12V rail when under full load. The other rails fall between 5mV and 15V across the full range of loads. Class leading results and well within tolerance specifications.

Efficiency (%)
100W	86.92
225W	92.31
450W	93.83
675W	92.23
850W	91.77

The efficiency of the power supply is very good, hitting almost 94 percent at 50 percent load, dropping back to almost 92 percent 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 Refridgerator
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	<28.0
450W	<28.0
675W	<28.0
850W	29.2

The power supply is basically silent right until around 750W load – at the accurate limit of our testing equipment. Then the fan spins up between 750W and 850W output, generating around 29.2dBa of noise. This is one of the quietest high end power supplies we have tested.

Just like the 550W model, even with our ear close to the chassis, it was difficult to tell that the power supply was actually turned on. The fan speed rated until 700 rpm until the last 100W of power output, peaking around 930 rpm.

Simply incredible results.

Temperature (c)
	Intake	Exhaust
100W	35	39
225W	37	42
450W	40	47
675W	43	51
850W	45	56

Considering the incredibly low noise emissions, the ambient temperatures are fantastic, rising to to a 11c above ambient intake level at full load.

Maximum load	Efficiency
933W	90.7

At 933w, the efficiency level is still strong, measuring 90.7%. Not a practical situation to be running 24/7, but worth noting.

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