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Thread: be quiet! Pure Power 11 FM 750W

  1. #1
    Xtreme Reviewer
    Join Date
    Apr 2011

    be quiet! Pure Power 11 FM 750W


    be quiet! have proven very successful in the Case, AIO, Air Cooler, Fan sector of the market, and today we take a look at one of their new power supplies from their latest Pure Power 11 FM series. The Pure Power 11 FM series is the successor to the Power 10 series. The "FM" designation refers to a "Fully Modular" design. Packed with plenty of excellent features, including an 80-Plus Gold efficiency those series utilize a 80 Plus Gold efficiency. Available in 550W, 650W, and 750W variants, for this review we will specifically take a closer look at the 750W design. Pure Power 11 FM offers 750W of continuous power with two independent 12V rails for signal stability and four PCI express connectors.

    Before we got onto those all-important tests, however, let's first take a look at the be quiet! Pure Power 11 FM and check out those tasty features and specifications it has to offer! The Be Quiet Pure Power 11 FM comes equipped with LLC + SR + DC/DC technology. These technologies offer advanced stability and voltage regulation. The Pure Power 11 FM also comes with modern UVP, OVP, SCP, OPP, OCP, and OTP protection circuits. That is a robust connection that protects the whole system and power surges.

    Packaging & Contents

    The box is small and at the front there is a photo of the product, with the modular panel shown. The series description is highlighted in large fonts and below it we find the unit's capacity. The small 80 PLUS Gold badge is near the top-left corner.

    At the rear be quiet! gives information showing the power specifications table and the various certifications that the product has achieved. There are also a couple of stickers with one of them listing the serial number.

    We cannot say that the protection inside the box is the best possible, since only a little bubble wrap is used. We would like to see packing foam used instead.

    Product manual and fixing screws.

    In addition to the power supply, three different ATX cables are included, two PCIe cables with two connections each and two SATA cables, one with three connections and one with four connections. A plug cable is of course also included. The power suppy is equipped with black flat cables and a black-sheathed 55 cm long, 20 + 45-pin ATX power cable. The CPU 8 pin (4+4) is the longest cable at 60 cm. These are nice and flexible and make a good impression.

    A Closer Look Outside

    The Pure Power 11 750 FM power supply follows the appearance design of the Pure Power series. The whole enclose has a lovely powder metal texture to it. The power supply has an overall size of 160 x 150 x 86mm, which can be compatible with different sizes of chassis. The exhaust side has usual hexagonal ventilation openings and we have two subtle stickers above and below the power cord port. be quiet! has given the Pure Power 11 750 FM a fan grille, which has 17 parallel bars. A 120 mm fan from Be Quiet was installed behind the fan grille, which is immediately noticeable with its distinctive fan blades. From this angle we see the fan having a white rim ring.

    A look at the bottom of the power supply.

    At the front we can see the connections for the modular cables. The arrangement is easily accessible and clearly labeled.

    On the right side of the case we can find a be quiet! Embossed logo.

    On the left side we have the whole surface covered with the specs and power delivery sticker. The rated power of the power supply is 750W. The product has passed 80 PLUS gold certification. The dual 12V output reaches 750W, which can meet the power supply requirements of flagship platforms such as RTX 3090.

    A Closer Look Inside

    This is a CWT design for be quiet!, and the build quality is very high indeed. The layout seems well thought out for surface cooling too. The be quiet! Pure Power 11 FM 750W power supply adopts an active PFC+LLC resonance+DC-DC solution to ensure the product's efficient and stable output under different loads. The DC-to-DC mean's the 3.3V and 5V rails' juice is derived from the main 12V.

    The AC receptacle hosts two Y caps. The other parts of the EMI filter are located on the main PCB, including four Y and two X caps, two CM chokes and a small MOV.

    The bridge rectifier is a GBU1506s.

    Champion manufactures the PFC controller (CM6500UNX), which is installed on the main PCB's solder side.

    The supervisor IC is a Weltrend WT7527, supporting all essential protection features but OTP (Over Temperature Protection).

    The secondary EMI filter circuit of the power supply is complete. The main capacitors are two 390 microfarad Teapo capacitors. They belongs to Teapo's mainstream products. Their lifetime is short under high temperatures, which is why this power supply is only rated for 85C.

    To keep the cost low, Teapo and Elite provide the electrolytic caps.

    The back of the modular board. On the modular board's, several electrolytic and polymer caps suppress ripple on the rails.

    Soldering is without fault and the component selection throughout is excellent.

    The 120mm rifle bearing fan (BQ QF2-12025-MS) comes from be quiet! of course.

    Instrumentation used

    Below we report the instrumentation used in the test phase for the be quiet! Pure Power 11 FM 750W.

    PowerKiller 2.0. Test bench designed for power supplies up to 2185W.
    Stingray DS1M12 USB Oscilloscope
    PCE-PA 6000 Wattmeter
    Range 1W ~ 6kW
    Accuracy - 1.5%
    3 x HT81
    1 x ABB Metrawatt M2004
    1 x Eldes ELD9102
    1 x Kyoritsu Kew Model 2001
    1 x EDI T053
    Scythe Kama Wireless Thermometer
    Center 325 sound level meter

    Voltage Regulation

    The voltage regulation tests are carried out by connecting all the electrical lines to our PowerKiller and simulating the behavior of the power supply with loads comparable to those of a real location.
    + 3.3V line
    average voltage 3,275 volts
    Deviation from the ideal value (3.33 volts)= -1.65 %

    + 5V line
    average voltage 4,928 volts
    Deviation from the ideal value (5 volts)= -1.44 %

    + 12V line
    average voltage 11.985 volts
    Deviation from ideal value (12 volts)= -0.125 %

    The be quiet! Pure Power 11 FM 750W under test withstood the overload test without major difficulties. The voltage values ​​have dropped to acceptable levels, but the trend has confirmed that the Pure Power 11 FM 750W model have been designed to deliver exactly what was declared.


    The energy certifications obtained by Pure Power 11 FM 750W under test are achieved with a fair margin, especially at medium load.


    Power supply ripple is a manifestation of voltage fluctuations. It is generated during the process of AC to DC. The fluctuation of ripple can directly reflect the performance of power supply workmanship and materials. In terms of measuring how cleanly the energy is delivered, the ripple results are again entirely solid. A particular highlight can be seen in both the 3.3V and 5V rails as the highest result recorded in our testing was only 5.8. Admittedly, the 12V results are clearly a little more excitable, but in regards to regulations, they are still massively below the maximum of 50 (under EU standards).

    Cross Load

    The be quiet! Pure Power 11 FM 750W passes the first test with equally good results: the declared threshold of 3% is maintained on all three lines of interest with a fair margin.
    + 3.3V line
    Maximum Vdrop 0.1 volt (3.00%)

    + 5V line
    Maximum Vdrop 0.09 volts (1.80%)

    + 12V line
    Maximum Vdrop 0.28 volts (2.31%)

    APFC & OverLoad

    The power factor control system (APFC) shows respectable results, in particular as regards the values ​​at full load. The almost absence of phase shift between the voltage wave and the current wave is already reached at 75% of the maximum load.

    We can confirm the presence of an adequate protection system against overload and an effective oversizing of the internal components. There is no doubt about the quality of the components used but, as always, we suggest choosing the power supply based on the real needs of your workstation without relying on its overload capacity, which is tested by us only in order to ascertain the goodness of the internal circuitry and protection systems.


    The rifle bearing fan fan works well to expel heat out the rear of the chassis. The overall results are very good indeed.


    The fan in this unit is very quiet under most load conditions, and it is only in the last 10% of power delivery that the fan starts to spin up to compensate for rising heat.

    Final Thoughts

    Offering 750 watts of power output and 80-plus Gold efficiency, the Pure Power 11 FM 750W would represent an absolutely ideal choice for the vast majority of gaming PCs. This seems to be every bit of the improvement on the Power 10 series be quiet! promised this would be. The fully modular design keeps the cable minimal and provides easy routing to the system. The provided cables are flexible and durable. As you could see throughout our tests, the Pure Power 11 FM 750W never skipped a beat. In every test, it gave excellent results. With excellent results in terms of efficiency, it’s also hard to overlook just how well this performed in the overpower protection testing. Ripple suppression throughout the load range is excellent and load regulation falls well within expected parameters for safe operation. In terms of noise levels as well, the fan results speak for themselves. It’s exceptionally doubtful in a fully running PC that you would be even able to notice this. The only criticism I could possibly make of this power supply is that I would like to see something better than these Teapo secondary side and 85C bulk capacitors. It’s not that they’re necessarily bad, but if they were high grade Japanese capacitors, I wouldn’t have a problem at all here. That said, be quiet! backs this model with a five-year warranty, and be quiet! is well known for its excellent support.

    Available to purchase now for a price in the region of 100 Euros, in comparative terms, while not representing an outright bargain, it is at the very least consistent and highly-comparable with the various other gold rated power supplies at this wattage output level. The be quiet! Pure Power 11 FM 750W is a very high grade power supply, and will target the discerning enthusiast audience looking to keep costs within a certain limit.

    Last edited by testman78; 07-19-2021 at 12:10 AM.



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