be quiet! Dark Power Pro 10 750 W Power Supply Review

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Yup, I’m at it again! It’s time to see if the 750 W flavor of the Dark Power Pro 10 is anything like the 1200 W flavor. I hope it is, as the 1200 W is an epic unit. Will the 750 live up to the name and example? We’ll see.

Features and Specifications

These come direct from the be quiet! website’s product page. The grey italics are my thoughts on the matters at hand.

Legendary Silence, Cutting Edge Performance
Dark Power Pro supplies are already renowned as the world’s quietest PSUs in the high performance category. The Dark Power Pro 10 750W model takes that a giant step further with an all-new design topology that delivers 80PLUS Gold performance, the world’s highest energy efficiency certification. Add to that an unparalleled array of enhancements that augment this unit’s compatibility, convenience of use, reliability, and safety, and the result is simply a power supply without equal. Simply put, this is the highest-powered, most technologically-advanced power supply be quiet! has ever built.

  • Virtually silent operation achieved through a broad array of meticulous optimizations, including use of be quiet!’s custom-designed 135mm SilentWings® fan
  • SilentWings fan features airflow-optimized fan blades, fluid dynamic bearing with copper core and high quality IC motor controller for the quietest possible operation
  • 80PLUS Gold certification and up to 93% power conversion efficiency let you do more work with the same power and reduce your power bills
  • 750 Watts of continuous power provide deep power reserves for demanding computing applications
  • NVidia SLI and AMD CrossfireX multi-GPU certifications allow you to build Multi-GPU systems with utter confidence
  • Cable management with extra long cable reach simplifies component installation and reduces annoying clutter, increasing airflow and improving cooling in even the largest PC cases
  • Overclocking key allows switchover between quadruple independent +12V rail mode and high-performance single-rail operation
  • German product conception, design and quality control

Virtually silent is a lot more honest than saying silent, I approve. I also approve of 80+ gold and long cables. The Overclocking key is nice for those who want a single rail. I want more than one myself. The German product conception, design and quality control bit is interesting. We’ll see how it looks inside later, that’s the real measure.

Feature Details

Virtually Silent Operation

  • Installed 135mm SilentWings® fan includes a wide array of electronic and mechanical optimizations for best-of-class air flow with very low noise production
    • unique airflow-optimized fan blade design reduces noise-generating fan turbulence
    • advanced fluid dynamic bearing with copper core provides for greatly reduced operating noise and super-long life
    • high quality IC motor controller reduces electrical noise
  • SilentWings fan is decoupled from the PSU body with special mounts, reducing transmission of vibration and noise
  • Dual-layer PSU housing with rubberized sleeve isolates your chassis from PSU noise and vibration, further enhancing silence
  • Optimized PSU airflow generates superior cooling at lower fan speeds, reducing turbulence and allowing even quieter operation
  • Variable fan speed is optimally governed to strike the best balance between proper cooling and deep quiet
  • Up to four case fans can also be connected to and regulated by the Dark Power Pro 10 750W PSU, reducing overall system noise even further

Engineering

  • All-new power conversion circuitry design for unmatched signal stability and power efficiency
  • Premiere quality Japanese capacitors rated to 105°C for maximum reliability and operating life
  • Top protection for components against over-currents, over- and under-voltages, short circuits, overheating and overloads; internationally tested and safety rated at 50°C
  • Long service life up to 300,000 hours
  • Overclocking key allows you to choose between multi-rail operation (with four independent +12V rails) and high-performance single-rail operation

We will, as usual, check the caps. The odds of this thing lasting 300,000 hours seem small to me, that’s over 34 years. Long lifespan, sure. 34 years of 24/7 operation? That I doubt.

Energy Efficiency

  • 80PLUS Gold certification—one of the highest available
  • Very high efficiency (up to 93%) means your computer draws less power from the mains to do its work
  • Saving power means saving money, but it also mean less waste heat, less cooling required, and overall quieter operation
  • Standby drain less than 0.1Watts
  • Meets Energy Star 5.0 guidelines
  • Fulfills the ErP 2013 guidelines
  • Zero Load design supports Intel’s Deep Power Down C6 mode

Yes, it’ll work fine with Haswell too.

Maximum Compatibility and Convenience

  • Professional modular cable management system with removable cable bundles simplifies component installation, reduces annoying clutter, increases airflow and allows for improved cooling
  • System supports up to 32 connectors for massive system builds
  • Connectors are compatible with older components as well as those still on the drawing board
  • Sleeved cable lengths up to 120cm allow for improved cooling and are perfect for large PC cases
  • Individual P4 and P8 plugs support all common mainboard types
  • Seven PCIe connectors for powerful multi-GPU configurations (NVIDIA SLI and AMD CrossFire)
  • Clearly labeled plugs and clever accessories promote simple installation

If it’s anything like the 1200W flavor, the cable selection is wonderfully overkill.

Outstanding Service and Support

  • 5 year manufacturer’s warranty
  • Free on-site exchange service within first year (limited to Germany and France)
  • Quick support is available via our international hotline, Mondays to Fridays from 0900 to 1730 German local time.

I do love a good warranty. Too bad the free on-site exchange is only for Germany and France, that’d be amazing!

Lastly, box shots for the cables and the outputs:

dp750-specs-cables

That enough cables for you?

dp750-specs-outputTable

This I like, four rails for a 750 W PSU is excellent. The current limits are high enough that you won’t run into issues, but low enough to prevent fires. Perfect!

Photos Part One: The Box

The box is fairly simple, but it explains things and has a handle, so I like it.

Box Front

Box Front

Box Rear!

Box Rear!

Box End!

Box End!

Another Box End!

Another Box End!

The Top, With Handle!

The Top, With Handle!

I like that the box clearly labels this PSU as “high-end”, this will prevent confusion. Actually I really do like the box, but my favorite part is on the inside:

Look At All The Protective Foam!

Look At All The Protective Foam!

Cable Box Hides Under Manual

Cable Box Hides Under Manual

See that? That right there is packaging the way I like it, excessive. This unit came to me from Germany with no external padding, just a thin cardboard shell box. You can see where the PSU box took a hit and tore a bit too. Did the PSU care? Not in the slightest. This packaging makes me very happy indeed.

Photos Part Two: The PSU

BBQ Anybody?

BBQ Anybody?

Bottom, With Label

Bottom, With Label

One Side

One Side

The Other Side, With Warranty Label

The Other Side, With Warranty Label

Electrical Output Here

Electrical Output Here

Air Output Here

Air Output Here

This PSU looks almost identical to its 1200 W sibling, though I’d be surprised if it didn’t. This both makes me happy and makes me apprehensive. Happy because it looks great, and has a fair bit of noise dampening built in. Apprehensive because the 1200 W was a complete pain to disassemble. That isn’t a problem for you, but for me it’s time consuming! There were something like 14 screws involved in just getting the lid off. Note that you cannot see even a single screw when looking at the outside. It really does look great, too.

Glamor!

Glamor!

More Glamor!

More Glamor!

Last One

Last One

I continue to like it.

Photos Part Three: Cables

Inside the cable box, we find this:

Cable Box, Open

Cable Box, Open

Accessories, Lots

Accessories, Lots

The cable box opens to disgorge a significant quantity of cables, bundled together with “Velcro” type straps. Near the box in the foam are the accessories. These consist of a stack of Velcro cable ties of the shiny sort, a handful of zip ties, five big thumbscrews, five black Phillips screws, one OCK rear panel connector (for switching between single rail and multi-rail), one OCK jumper (for full time single rail), five fan cables to use the internal fan controller with, and a German/European power cable. If you buy this in the USA I expect you’d get a USA type cable. This unit came straight from the Fatherland however, and is equipped as such.

CPU Power Cables, Lots

CPU Power Cables, Lots

PCIe Cables, Lots and Lots

PCIe Cables, Lots and Lots

Molex Cables, Plenty

Molex Cables, Plenty

SATA Cables, Lots Of These Too

SATA Cables, Lots Of These Too

Molex / SATA Combo Cable

Molex / SATA Combo Cable

The cable selection is almost obscene, you get seven PCIe plugs, every CPU power plug you can think of (within ATX/EPS spec, anyway), a stack of Molex and SATA cables (including two single-Molex cables and one single-SATA cable), and a Molex+SATA combo cable. It’s wild. It also goes toward explaining the price tag.

I approve of the cable related excess, I like excess.

I think it’s time to test this thing!

Load Testing Part One: Regulation

A decent load test of a PSU requires a decent load. Contrary to what some may believe, that means you need a known load that can fully stress the PSU. Computer hardware does not cut it. Worse, if the PSU fails during testing it might take out the computer hardware anyway. Commercial load testers cost a lot of money. I do not have a lot of money, so I built my own with juicy power resistors and a Toyota cylinder head. It works great. I’ll be using it to load this thing down fairly severely and will check voltages and ripple (more on that later) at various points. The down side to my tester is that the loads it can put on PSUs are fairly coarse, they go in increments of 48 W for 12 V, 50 W for 5 V and 22 W for 3.3V. Those wattages assume the PSU is putting out exactly the official rail voltage, a PSU putting out 12.24 V rather than 12 V will be at 49.9 W per step rather than 48 W. I file that under the “tough beans” category as I figure if a percent or two of load makes that much of a difference, the PSU manufacturer should have hit the voltage regulation more squarely. It does make calculating efficiency difficult at best.  However, given that the input power is read via a Kill-a-Watt, the efficiency numbers are dubious to begin with. Kill-a-Watts are not known for extreme accuracy on things with automatic power factor correction. For this reason, I am not listing the efficiency.

The ATX spec says that voltage regulation must be within 5% of the rail’s official designation, regardless of load. It doesn’t actually mention that the PSU shouldn’t explode, though I expect they figured it was implied. Exploding is a failure in most books.

It is also worth knowing that I will be testing this PSU at both outdoor ambient temperatures (typically between 5 °C and 20 °C here) as well as in the Enclosure of Unreasonable Warmth. TEUW is a precision engineered enclosure that I use to route the exhaust air from the PSU right back into the intake fan, it is adjustable to hold the intake air temperature at (almost) any level I want it. This way I can test the PSU’s response to hot conditions as well as cold conditions. For the hot testing I will be running the intake temp as close to the unit’s maximum rated temperature as possible. TEUW, in case you’re curious, is a cardboard box. Sometimes a Styrofoam medical supply shipment cooler, if the unit is too efficient for the cardboard box.

Loads (total) 12 V Rail 5 V Rail 3.3 V Rail Kill-A-Watts Temps In/Out
0/0/0w (0w)  12.18  5.05  3.37  11.1  10/12 °C
96/50/22w (168w)  12.20  5.03  3.33  189  10/12 °C
288/50/22w (360w)  12.20  5.03  3.33  399  10/15 °C
480/50/22w (552w)  12.20  5.03  3.32  615  10/18 °C
672/50/22w (744w)  12.18  5.03  3.32  850  10/23 °C
HIGH TEMPERATURE RESULTS BELOW:
672/50/22w (744w)  12.17  5.03  3.31  859  42/50 °C

This is… Really rather amazing. To start with, the fan never really sped up during the ambient tests, even with a long burn at ~100% load. Oh and the fan was inaudible from any range longer than 1″. That’s an inch, mind you, between my ear and the fan. It’s that quiet. Amazing. Even at full burn at 42 °C intake temps the fan was very very quiet. This unit took the brand name to heart.

The regulation is rather nice too, we have 0.24% regulation on the 12 V rail (just a bit under the excellent mark of 1%…), 0.4% on the 5 V rail, and 1.8% on the 3.3 V rail. All combined, that’s 0.8% regulation. Excellent! Really really excellent. Combine excellent regulation with excellent temperature control and excellent noise control and what do you have? A happy reviewer.

Load Testing Part Two: Ripple

Ripple is fluctuation of the PSU’s output voltage caused by a variety of factors. It is pretty much impossible to have zero ripple in a SMPS computer power supply because of how a SMPS works, so the question is how much ripple is there? In the regulation testing phase we found out how the PSU does at keeping the average voltage at a set level, now we’re going to see what that voltage is doing on really short time frames. The ATX spec says that the 12 V rail cannot have more than 120 mV peak to peak ripple, the 5 V and 3.3 V rails need to stay under 50 mV.

If that isn’t complicated enough for you, there are three forms of ripple to keep track of as well. Long-term ripple from the PSU’s controller adjusting the output voltage and over/undershooting, correcting, overshooting, etc. Medium-term ripple from the voltage controller charging and discharging the inductor(s) and capacitor(s) that make up the VRM, and very short-term ripple caused by the switching itself. The first and second forms are the most important, if they are out of spec it can cause instability at best or damage in extreme situations. The very short-term (I call it transient ripple) flavor is less crucial, excessive amounts can still cause issues though it takes more of it to do so. The ATX spec does not differentiate, as far as the spec goes 121 mV of transient ripple is just as much of a failure as 121 mV of medium or long term ripple.

I test ripple in a few difference ways, first I test it during the cold load testing. It is tested at zero load and maximum load first. During the hot load testing I test the ripple at maximum load again. I have recently started testing ripple at fairly random loads with the unit still hot, it’s a bit unorthodox (a bit? maybe a lot) but has found issues in the past that did not show up with other test methods.

Now we’re into ripple testing, first at zero load with 10 °C ambients.

12 V Ripple, Cold, Zero Load, 5ms/10mV, ~11mV Ripple

12 V Ripple, Cold, Zero Load, 5ms/10mV,      ~11mV Ripple

5 V Ripple, Cold, Zero Load, 2µs/10mV, ~9mV Ripple

5 V Ripple, Cold, Zero Load, 5µs/10mV, ~9mV Ripple

5 V Ripple, Cold, Zero Load, 5µs/10mV, ~9mV Ripple

5 V Ripple, Cold, Zero Load, 5µs/10mV, ~9mV Ripple

Ha, certainly no issues there. Everything is so laughably within spec that it’s, well, almost silly. No issues with Haswell here, that’s for sure.

How about at full load?

12 V Ripple, Cold, Full Load, 2ms/10mV, ~44mV Ripple

12 V Ripple, Cold, Full Load, 2ms/10mV,      ~44mV Ripple

    5 V Ripple, Cold, Full Load, 5µs/10mV,     ~14mV Ripple

5 V Ripple, Cold, Full Load, 5µs/10mV,      ~14mV Ripple

    3.3 V Ripple, Cold, Full Load, 5µs/10mV,     ~23mV Ripple

3.3 V Ripple, Cold, Full Load, 5µs/10mV,    ~23mV Ripple

Still excellent, not quite as epic (OK the 5 V rail is, it’s fantastic), but still very very good. I’m pleased. I’m so pleased that I’m going to cook it for a while and see how it does after that!

    12 V Ripple, Hot (40°C, Full Load, 2ms/10mV,     ~42mV Ripple

12 V Ripple, Hot (40 °C), Full Load, 2ms/10mV, ~42mV Ripple

    5 V Ripple, Hot (40°C, Full Load, 5µs/10mV,     ~15mV Ripple

5 V Ripple, Hot (40 °C), Full Load, 5µs/10mV,   ~15mV Ripple

    3.3 V Ripple, Hot (40°C, Full Load, 5µs/10mV,     ~23mV Ripple

3.3 V Ripple, Hot (40 °C), Full Load, 5µs/10mV, ~23mV Ripple

Right about the same despite being much hotter. I approve. No transient spikes, even on the DC-DC bits, that’s rare.

Dissection

Disclaimer: Power supplies can have dangerous voltages inside them even after being unplugged, DO NOT OPEN POWER SUPPLIES. It’s just not a good idea. Opening a power supply and poking around inside could very well kill you. Don’t try this at home. Don’t try this at work. Just don’t do it.

The above warning is a bit more superfluous than usual with regards to today’s PSU. It’s a decent trick to figure out how to take it apart, even if you want to.

The first one took me a good bit to figure out completely, even this one (#3 for this series that I’ve taken apart) took a while. It’s a pain. That’s OK though, as taking your PSU apart is not part of normal operations.

Once it’s apart, we have the fan and an overview:

The Hub

The Hub Of The Fan Of Much Quiet

An Overview

An Overview

This looks to be a FSP build, but a custom one. It most closely resembles the Aurum Pro, but it has some major differences when held up next to that platform. The PCB mentions be quiet! specifically, making me suspect it’s a custom design.

Receptacle Transient Bits

Receptacle Transient Bits

PCB Transient Bits

PCB Transient Bits

The transient filter is nice and complete, it has four Y caps, two X caps, two inductors, an inrush control thermistor (with a relay to short it out for more efficiency) and a TVS diode for surge protection. Plus, of course, a fuse.

The Rectifier

The Rectifier

APFC Brainbox

APFC Brainbox

APFC Switches and Diode

APFC Switches and Diode

Primary Capacitors by Panasonic

Primary Capacitors by Panasonic

The primary rectifier is a GBJ25L06 (25 A, 600 V) unit with a dedicated heatsink. For APFC bits we have three 26NM60M (20 A, 600 V) MOSFETs and a CREE C3D06060 (6 A, 600 V) diode. The APFC controller doesn’t appear to have a part number on it.

The primary switches are another pair of 26NM60M MOSFETs, controlled by a CM6901T6X PWM controller. The MOSFETs are behind the primary capacitors, you can just barely see the mounting bolt for one in the above photo.

Below we have the secondary side:

Secondary Overview

Secondary Overview

DC-DC Bits

DC-DC Bits

The metal plate type heatsink houses the 12 V rectifiers, four FB3206G (190 A, 60 V) MOSFETs. Yes, 190 amps each, at 100 °C. Those things cost $4.50 or so each. We get a collection of Nippon Chemi-Con and Rubycon electrolytic capacitors, as well as a host of CapXon Polymers. While CapXon doesn’t make me happy when it comes to electrolytics, I have yet to see any issue with their polymer caps. Polymers are so much better just by default that manufacturer doesn’t seem to matter nearly as much. On the DC-DC board we have a APW7159 controller running the show, 5 V and 3.3 V each get two LR8729 (58 A, 30 V) MOSFETs and two LR8726 (86 A, 30 V) MOSFETs.

Here’s the modular board:

Back Side Of The Modular Board

Back Side Of The Modular Board

Front Side Of The Modular Board

Front Side Of The Modular Board

Lots more polymer caps, a decent stack of ceramic caps, no wonder ripple is so nice. We can also see the fan control bits, the TO-220 packaged piece is a MJE2955 PNP transistor, rated for ten amps and 75 W when operating with a (big) heatsink, no heatsink here though. The TO-92 part is a 2907A PNP transistor rated at 625 mA.

Lastly (for this section, anyway), the soldering:

dp750-guts-soldering-overview

Overall, very good. There are a couple oddities however:

Not Quite Enough Solder

Not Quite Enough Solder

Not Sure What Happened Here

Not Sure What Happened Here

Neither of these are large issues, but they do stand in the way of a “perfect” soldering rating.

Final Words and Conclusion

To lead things off, I have to say that I’m mildly surprised. Usually if the huge unit of a PSU series is excellent and the smaller unit(s) are on a different platform, their performance is significantly different (and often worse). This is not the case this time. The two units, despite being on different platforms from different manufacturers, are extremely similar performance wise. I’m impressed.

The looks are wonderful in my opinion. If you don’t like the BBQ grill style fan guard, tough. On the other hand, it’s much easier for a cable to sneak through the straight bars and make noise on the fan than it is with a curved grill, or my personal favorite a mesh. It does look great though. The cable selection is epic. It has everything you could ever need, and then it has a few extras just in case. Amazing.

The regulation is fantastic, that’s really all there is to say on that front. The ripple control is very very good. It’s bordering on excellent, really.

The build quality is excellent as well, all the heatsink screws are threadlocked, the case fits together like a puzzle and results in no visible screws, the soldering is (with the two minor exceptions above) excellent, the parts are overkill, it’s nice.

This PSU is QUIET. Really, really, really quiet. It’s pretty amazing really. I’ll even go so far as to say that when the marketing bits say “Virtually Silent”, they’re right.

Ready for a downside? This thing is not cheap. Currently it is going for $199.99 on Newegg, tying it for the dubious title of Most Expensive 750 W PSU. On the other hand, you get amazing performance, great looks, and the truly epic cable selection. Oh yeah, and near-silence. Still, that’s a painful price.

The packaging is every bit as deliciously overkill as the rest of the PSU, tons of foam on all six sides. Wonderful!

Let’s summarize into some nice easy to read bullet points! That sounds like a good idea.

We’ll start with the pros:

  • Excellent regulation.
  • Wonderful looks.
  • Cable selection is epic.
  • Ripple control is great.
  • Very, very well protected for shipping.
  • Extremely quiet.

There’s a con too though:

  • Not cheap. Far from it, really.

That’s it, just one con. I’m not going to dump it out of the Approved category due to it being tied for the most expensive unit, and there being a few other units fairly close by price wise. That means it’s a viable price point, in theory. In any event, I’m highly impressed with the be quiet! Dark Power Pro 10 750 W, and give it an Approved award and my congratulations!

ocapproved

Click the stamp for an explanation of what this means

Bobnova

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Discussion
  1. Bobnova, thanks for your reply, I picked this psu up second hand, they said it was working:))

    Will take your advice as on the balance of probabilities it will not be just the fuse. Pity though.

    Once again thanks for your time much appreciated.


    Fuse is on the far right, mounted vertically and shrink wrapped.

    That said, if the fuse blew there is a very good reason for it inside the PSU itself, and the next one almost certainly will too.

    There are screws hidden under the rubber bands, and the end panels clip in. be quiet! did a lovely job at hiding everything when it's assembled, but it's a major pain to take it apart.

    Can you describe what happened to/with your PSU?
    This is a very helpful article thank you. I have a problem with my 750 be quiet I think the fuse is blown but cannot get the case apart have so far removed 10 screws cannot find anymore any tips as to why it wont come apart?
    i7-3770K OC to 4.3, also have a Xonar Essence STX and the H100i. Pretty much it for anything that would draw any meaningful amount of power.

    750W PSU yes, over 4 rails though. So it would depend how much each Rail can support at that point no?
    I believe the 850w flavor is the same Seasonic X platform as the 1250w, rather than the FSP semi-custom platform of the 750w and lower.

    Not that the X platform is a downgrade from this, just something to think about.

    A 750w should do 2x680 easily.
    Hmm I'm going to need a new PSU for my duel GTX 680's, definitely looking at 850Watt version of this. A bit pricey, but my current Earthwatt 750 isn't going to be enough for running 2 680's.

    My case is also massive, so long cables and a good variety is a bonus :)