be quiet! Dark Power Pro 11 1200W Power Supply Review

Introduction & Packaging

be quiet! are regarded as one of the best brands in the business, from their high-end CPU coolers, system fans and of course their power supplies, many of which are regarded as some of the coolest, quietest and best make products available today. Obviously, the quiet part is a given, with a name like be quiet!, if they made noisy products, it would be quite a disappointment. To achieve quiet performance, be quiet! uses high-quality components, premium grade build quality and design, so it’s no surprise that they’ve won many awards in the past; will we see a repeat performance today?

The Dark Power Pro 11 is the latest entry in their popular Dark Power Pro series. There are a few notable features to this power supply that make it stand out from the competition. First we’ve got the new SilentWings 3 135mm fan which features the new 6-pole motor, a redesigned bearing, the lowest startup rotational speed in the market (under 250FPM) and more; promising virtually inaudible performance and improved cooling. Of course, power delivery is improved too, with high-quality PFC capacitors, higher efficiency, improved voltage stability, regulation and more!

Packaging and Contents

As you can see, the be quiet! Dark Power Pro 11 comes in the usual packaging design of any other be quiet! product. Down the left side of the box, it’s marked “high-end”, although the words “80 Plus Platinum” and “1200w” are also strong indicators that this is a high-end/enthusiast focused product.

The Dark Power Pro 11 is semi-modular and comes with a hard-wired 24-pin, not big deal since literally all systems will need this cable and making it modular would only add to the cost. There are two CPU power cables, an 8-pin and a 4+4, Four SATA/Molex cables with FDD options. One of the more important cables, there are four PCIe cables, three with dual 6+2 connectors and a single 6pin PCIe cable. Finally, you’ll also find external fan connector cables, more on those in a moment, and the Overclocking Key add-on.

In the box, we found two power cables, one for EU and one for UK, although we expect this will differ based on region.

Included extras from left to right, are the fan adaptor cables, OC jumper, Overclocking Key switch, screws, cable ties, thumb screws and two Velcro cable ties.

A Closer Look – Exterior

Power Supply Unit

The overall design of the Dark Power Pro 11 is really nice, with the top housing the gorgeous 135mm SilentWings 3 fan.

The shape of the fan blades, the rails above them and the fan opening have all been crafted to help reduce noise and improve airflow; with the added bonus that the design looks cool.

Again, you can see that this is an 80Plus Platinum unit, promising 1200 watts of power. What I do love however, is that the side lettering is embossed; it’s a little touch, but it gives the whole thing a nice premium finish.

As you can see below, the Dark Power Pro 11 has multiple 12v rails, although there’s the external switch which can be used to switch it to a single rail, giving you the option of load balancing or single, the latter will no doubt appeal to the overclocking crowd.

Down the left side of the PSU, we’ve got four fan connectors which come with their own extension adaptor cables. This allows you to power up to four fans, which will be electrically independent of your system, this again could prove useful for overclockers, especially if all the motherboard connections are covered to protect them from LN2. One more nice touch is the rubber grommet around the 24-pin connection, it looks a lot cleaner than the often circular cut-out with the cable simply passing through it we see on most PSUs.

Good ventilation around the back of the PSU will help move heat from the back of your system. Obviously, you can also see that this PSU is rated to work from 110 to 240Vac and comes with a master power switch at the back.

Cabling

The 24-pin cable is sleeved but does show a lot of coloured cable at the end. It’s not the end of the world, but I would have liked all black cables or a more extensive braiding up to the connectors. Although, admittedly, the market this PSU is intended for, if you’re doing a high-end build, you’re likely to apply after market cable sleeves.

All the cables are of a high quality, again there’s a lot of colour on show, but the cables are all pretty durable, with good quality plastic connectors and of a good length to suit large high-end chassis.

A Closer Look – Interior

Being a premium grade product, be quiet! have invested in some great hardware for the Straight Power 11 and the PSU has been manufactured by FSP. Now that we have the top cover removed, let’s take a closer look at the interior. It’s certainly worth pointing out that all Dark Power Pro 11 PSUs that are rated at 850w or above have eight daughter boards, which offer a range of features and performance improvement.

The two main bulk capacitors, of which there are clearly two, are rated up to 420v, 470uF and up to 105c.

The output capacitors, the four larger brown ones pictured below, are rated at 3300μF. be quiet! only uses Japanese brand capacitors, which are all certified to 105C. There’s also 39 aluminium secondary side output solid capacitors, which help negate any noise from extreme load changes, such as those generated by your GPU.

There’s a range of improvements on here, with a new PFC diode, capacitor, 12v Output Coil Diode and EMI Capacitor; all are higher quality than previous models to provide better performance, efficiency and in true be quiet! style, less noise. The use of noiseless PFC capacitors is a welcome addition, as they’re known to produce high-frequency noises, although that’s often a trait of cheaper PSUs and not something be quiet! would tolerate in their design.

The new Silent Wings 3 fan is one of the biggest improvements overall, as it uses the new 6-pole motor for a smoother and quieter operation, as well as a very low start up RPM, helping further reduce unwanted noise from the unit. Overall, everything has been built to provide clean and stable power, then refined to provide ultra quiet and reliable performance, so I’m expecting great things from this PSU once we get it on our load tester.

Test Procedure

At eTeknix we take the power supply testing procedure very seriously and have invested a lot of resources into acquiring the appropriate testing equipment. For all power supply reviews we test the power supplies with dedicated power supply testing equipment. This means we are able to get the most accurate results from our testing as opposed to using software benchmarks (such as OCCT) or multi-meter readouts which are broadly inaccurate.

Our test machinery is as follows:

• Sunmoon SM-5500ATE Active Load Tester (1200W rated)
• Stingray DS1M12 USB Oscilloscope
• Voltcraft DT-10L laser tachometer

The eTeknix test procedure involves:

• Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power “pulled at the wall”) and voltage regulation (deviance from expected voltages of 3.3/5/12 on the main rails).
• Measuring ripple with an oscilloscope at 20/40/60/80/100% load.
• Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan.
• Testing each power supply’s OPP (Over Power Protection) mechanism and seeing how many watts each power supply can deliver before shutting down

Other things to consider are that

• We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply to ensure there is not efficiency loss from poor cables selection
• Our Sunmoon SM-5500ATE power supply tester is not capable of testing more than 300W on each of the 12 volt rails so where a power supply provides more than 300W on a 12 volt rail that power is distributed over multiple 12 volt rails on the load tester. For example a power supply with one 12 volt rail supplying 750 watts would be spread equally over three 12 volt rails on the load tester, a power supply with two 450W 12v rails would be spread over four 12v rails on the load tester, two 225W 12v rails for each of the 12v rails on the unit.
• We use the same time scale and horizontal millivolt scale on our oscilloscope for all ripple tests, that is a 20ms T/DIV (horizontal) and a 0.02 V/DIV (vertical) meaning the scale is from -80mV to +80mV, ATX spec dictates that the 12v rail must fall within 150mv of ripple and the 3.3/5 within 50mv so that scale allows us to include both 150 and 50mV peaks. (Some older PSU reviews use different scales which were later ditched as the visual representation they give is inadequate, in these reviews written measurements are provided only).
• Deviance is the terminology used to represent the way voltages diverge from the expected values

Efficiency, PFC and Voltage Regulation

Voltage Regulation

To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.

The voltage regulation on the Dark Power Pro 11 is very impressive, with only the 3.3v creeping above 1%, although it’s still very much within acceptable parameters. Results are very consistent across the load range and it’s as good as you would expect from a premium grade PSU.

Power Efficiency

Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.

The PSU conforms perfectly with the 80 Plus Platinum specification, certainly no complaints here.

Power Factor Correction

Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).

Very strong and consistent PFC performance, again, this is what we would expect to see from a high-end product such as this.

Ripple

Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs. millivolt ripple is measured by the peak to peak size of the voltage curve.

Sample Ripple Graph

The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications. Millivolt figures are stated to the closest increment of 5 given their variability.

Again, consistent and reliable performance from the Dark Power Pro 11 across a range of voltages, not that we were expecting anything other than that of course.

3.3 volt @ 100%

5 volt @ 100%

12 volt @ 100%

Over Power Protection and Max Wattage

Power supplies often quote as having various protection mechanisms such and the most important of these is Over Power Protection. In our testing we crank up the power draw until the power supply either shuts down (meaning the OPP mechanism is present and working) or blows up (meaning it is either not present or not working). We then note the maximum power consumption before the power supply shut down (or blew up).

This may be rated at 1200W, but we managed to exceed that by an impressive 268.2, this is good news for overclockers and enthusiasts who may encounter power spikes and it’s a sure sign that be quiet! have a rock solid product on their hands.

Fan Speed

When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Sunmoon test equipment and air conditioning corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. The ambient temperature during testing held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. 

In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.

• Below 800 RPM – Inaudible/Silent
• 800 to 1000 RPM – Barely audible
• 1000 – 1200 RPM – Audible but still quiet
• 1200 – 1400 RPM – Moderately noisy
• 1400 – 1800 RPM – Noisy
• 1800 RPM or higher – Intolerable

Incredible performance once again, it’s not until we get past 75% load that the fan gets past 800RPM. Unless you’re pushing this power supply at 100% for more than a short burst, which is highly unlikely short of enthusiast overclocking, you’re likely to never hear it.

Final Thoughts

Pricing

The Dark Power Pro 11 is available for retail immediately at a suggested retail price of $199/£161/€225 (850 watt), $239/£186/€259 (1000 watt) and $279/£207/€289 (1200 watt). Buyers of these high-end power supplies receive a five-year warranty and free 48-hour on-site replacement service in the first 12 months. The Dark Power Pro 11 series will be extended with lower-wattage models in August.

Conclusion

Previous entries in the Dark Power Pro series have been regarded as some of the best power supplies money can buy. They look gorgeous, they’re super quiet and they’ve consistently delivered great performance and award-winning reliability. Now that the Dark Power Pro 11 is here, we can see that be quiet! are not content with being great, as they’ve once again improved almost every aspect of the power supply.

The FSP manufactured power supply is one of the best we’ve seen, it promised to deliver super quiet performance, as well as clean and efficient power; it certainly ticks all those boxes and as far as performance is concerned it has exceeded my expectations.

Of course, the only downside for some, may be that this is still quite an expensive power supply, but when you look at the price of the current Dark Power Pro 10, which currently retails between £230-250 here in the UK, the Dark Power Pro 11 is already expected to cost less around £70-90 less! Although, this could be reflected with price drops in the previous generation too, but it’s still nice to see the prices of enthusiast grade power supplies coming down and this is a great price for a 1200w Platinum rated PSU.

The addition of an overclocking switch to jump from multiple to single rail setups, as well as being able to power four fans directly from the PSU are very welcome additions and perfect for the enthusiast overclocking market who will likely have this PSU fitted to a test bench.

If I could see any aspect of this PSU that could be improved, it would be the design of the cables. It’s a small gripe, but I know many enthusiasts that love neat looking cables and the sleeving on the be quiet! Dark Power Pro 11 shows off a lot of the interior cable colours, cheapening the PSUs premium-grade looks.

Pros

• Modular cables
• 5 Year Warranty with 12 Months on-site replacement
• Excellent ripple suppression
• Good PFC performance
• 80 Plus Platinum Efficiency
• Lower Price than previous generation
• Super-quiet performance
• Overclocking Key Switch
• Built-in fan connectors

Cons

• Cable sleeving

“The be quiet! Dark Power Pro 11 is easily one of the best power supplies on the market today. It promised premium performance and didn’t disappoint, with the added bonus of the OC key, fan hub, Silent Wings 3 fan, a great warranty and a very competitive price.”

be quiet! Dark Power Pro 11 1200W Power Supply Review

Thank you be quiet! for providing this review sample.