be quiet! Pure Power 11 FM 750 W Review 7

be quiet! Pure Power 11 FM 750 W Review



Be Quiet! Logo

We would like to thank be quiet! for supplying the review sample.

The be quiet! Pure Power 11 FM (Fully Modular) line lists three models of different capacities: 550 W, 650 W, and 750 W. I will take a look at the strongest member of the line to check on how it fares against the competition in the 750 W Gold category, including the new Corsair RM750x (2021) with the Magnetic Levitation fan, Cooler Master V750, MWE Gold 750, and the XPG Core Reactor 750. A strong competitor is also the Seasonic GX-750, but I don't have 230 V data for this model.

According to be quiet!, all Pure Power 11 FM models operate quietly. Thanks to the fully modular cable, installation and cable management will be easier than with the semi-modular and non-modular Pure Power 11 models. For the new Pure Power 11 FM line, be quiet! cooperated with CWT and used a new platform. The Pure Power 11 and Pure Power 11 CM units are based on FSP platforms that are not as capable.

The 750 W fully modular Pure Power unit is fully compliant with the ATX12V v2.52 specification. Hence, it's highly efficiency under incredibly light loads and compatible with Alternative Sleep Mode. The maximum operating temperature for continuous full-power delivery is set to 40°C, and a quality SilentWings fan measuring 120 mm across handles cooling.


be quiet! Pure Power 11 FM 750W
Features & Specifications
Max. DC Output750 W
Efficiency80 PLUS Gold, Cybenetics Gold (89%–91%)
NoiseCybenetics A (20–25 dB[A])
ModularYes (fully)
Intel C6/C7 Power State SupportYes
Operating Temperature0–40 °C
ProtectionsOver Voltage Protection
Under Voltage Protection
Over Power Protection
Over Temperature Protection
Over Current Protection
Short Circuit Protection
Cooling120mm rifle bearing fan (BQ QF2-12025-MS)
Semi-passive OperationNo
Dimensions (W x H x D)150 x 85 x 160 mm
Weight1.63 kg (3.59 lb)
ComplianceATX12V v2.53, and EPS 2.92
Warranty5 years
Price at Time of Review (excl. VAT)No information available
be quiet! Pure Power 11 FM 750W
Power Specifications
Rail3.3 V5 V12 V112 V25 VSB-12 V
Maximum Power20 A20 A36 A32 A3 A0.3 A
120 W750 W15 W3.6 W
Total Maximum Power750 W
be quiet! Pure Power 11 FM 750W
Power Distribution
12V1ATX, PCIe1, PCIe2, Peripheral
12V2EPS, PCIe3, PCIe4

Normally, 12V2 would be stronger since it has both EPS and two PCIe connectors.


The box has a photo of the PSU at its face, with the modular panel exposed to show interested buyers that this is a fully modular power supply. Around the back, you will find various certifications badges, the power specifications table, and the serial number.

It would be nice to see some foam spacers for extra protection instead of just a bubble wrap. This would require a larger box, though.

The white accent around the fan is a nice detail. At the front is the honeycomb-style exhaust grille.

The power specifications label is on one of the PSU's sides.

The modular panel has ten connectors. In the photos above, you will also notice that I broke the warranty sticker since I dismantled the PSU for the parts analysis.

The PSU is 160 mm deep, which is average. The ATX specification has for many years now cited 140 mm for ATX12V PSUs, but that is quite short for high-capacity units.

Cables and Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)GaugeIn Cable Capacitors
ATX connector 20+4 pin (550 mm)1116–18AWGNo
8 pin EPS12V (600 mm)1116AWGNo
4+4 pin EPS12V (600 mm)1116AWGNo
6+2 pin PCIe (500 mm+150 mm)2416–18AWGNo
SATA (500 mm+150 mm+150 mm)1318AWGNo
SATA (500 mm+150 mm+150 mm+150 mm)1418AWGNo
SATA (500 mm+150 mm) / 4-pin Molex (+150 mm+150 mm) / FDD (+150 mm)12 / 2 / 118–20AWGNo
AC Power Cord (1400 mm) - C13 coupler1118AWG-

All cables but the ATX cable are black and flat—the ATX cable is fully sleeved, though.

At 150 mm, the distance between peripheral connectors is adequate.

Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the insides of a PSU better.

be quiet! Pure Power 11 FM 750W Parts Description
General Data
Manufacturer (OEM)CWT
PCB TypeDouble-sided
Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Bridge Rectifier(s)1x GBJ1506 (600 V, 15 A @ 100 °C)
Inrush Current ProtectionNTC thermistor (SCK-075) (7 ohm) & relay
APFC MOSFETs2x ON Semiconductor FCPF165N65S3 (650 V, 12.3 A @ 100 °C, Rds (on): 0.165 ohm)
APFC Boost Diode1x ON Semiconductor FFSP0865A (650 V, 8 A @ 155 °C)
Bulk Cap(s)2x Teapo (400 V, 390 uF each or 780 uF combined, 2,000 h @ 85 °C LH)
Main Switchers2x ON Semiconductor FCPF190N60E (600 V, 13.1 A @ 100 °C, Rds (on): 0.19 ohm)
No Load Consumption FET
1x Sync Power SPN5003 (500 V, 20 mA @ 70 °C, Rds (on): 250 ohm)
APFC ControllerChampion CM6500UNX
Switching ControllerChampion CU6901VAC
TopologyPrimary Side: APFC, half-bridge & LLC converter
Secondary Side: synchronous rectification & DC-DC converters
Secondary Side
+12 V MOSFETs6x ON Semiconductor NTMFS5C430N (40 V, 131 A @ 100 °C, Rds (on): 1.7 mOhm)
+5 V & +3.3 VDC-DC Converters:
2x UBIQ QM3054M6 (30 V, 61 A @ 100 °C, Rds (on): 4.8 mOhm),
2x UBIQ QN3107M6N (30 V, 70 A @ 100 °C, Rds (on): 2.6 mOhm)

PWM Controllers:
uPI-Semi uP3861P
Change Over Switch1x Sync Power SPN3006 FET (30 V, 57 A @ 100 °C, Rds (on): 5.5 mOhm)
Filtering CapacitorsElectrolytic:
7x Teapo (1–3,000 h @ 105 °C, SC),
2x Elite (2–5,000 h @ 105°C, ED),
1x Elite (2–5,000 h @ 105 °C, EK),
7x Teapo (4–10,000 h @ 105 °C, TA)

Polymer: 18x APAQ
Supervisor ICWeltrend WT7527RT (OCP, OVP, UVP, SCP, PG)
Fan Modelbe quiet! BQ QF2-12025-MS
(120 mm, 12 V, 0.20 A, rifle bearing fan)
5VSB Circuit

1x Silan Microelectronics SVF4N65RDTR FET (650 V, 2.5 A @ 100 °C, Rds (on): 2.7 ohm),
1x PS1045L SBR (45 V, 10 A)

Standby PWM ControllerOn-Bright OB5282

This is a new CWT platform made for be quiet!. It has a clean design without any cables blocking airflow, and the distance between components is large enough to allow for good airflow. For CWT's standards, the heatsinks are quite large on the primary side since there are no real heatsinks on the secondary side. There are several daughter boards to keep the main PCB as sparsely populated as possible; it would also need a larger PCB without these daughter boards.

The transient filter is in two parts, with a single X and two Y caps at the AC receptacle and the second part on the main PCB including all other components. The MOV is covered in heat-shrink tubing, so it will stay in place when dealing with a high power surge that partially or completely destroys it. You don't want parts flying around inside the PSU.

Large inrush currents are suppressed by an NTC thermistor and bypass relay combination.

The single bridge rectifier is bolted onto a beefy heatsink.

ON Semiconductor provides the APFC converter's FETs. The same goes for the boost diode. Finally, the bulk caps are provided by Teapo and have enough capacity to provide a hold-up time of over 17 ms. The significant let-down here is the 85 °C rating. This is probably a reason for the relatively short five-year warranty. That having been said, I believe that five years are quite enough for a power supply.

The APFC controller is the Champion CM6500UNX, and there is a FET that isolates the APFC converter while the PSU is in standby mode.

Two On Semiconductor FETs installed in a half-bridge topology are the main FETs.

The LLC resonant controller is a Champion U6901VAC.

The unit's main transformer is directly connected to the board that hosts the +12 V FETs.

The FETs that regulate the +12 V rail are six On Semiconductor NTMFS5C430Ns. They are installed on a vertical board close to the main transformer. Exactly the same number and type of FETs are used in the Corsair RM850x (2021).

Two DC-DC converters generate the minor rails. They use four UBIQ FETs, and the common PWM controller is a UPI Semi uP3861P. The same VRMs are also used in the Corsair RM850x (2021).

To keep the cost low, Teapo and Elite provide the electrolytic caps. I am not so fond of the Teapo SC caps because of their low lifetime. There are also 18 polymer caps by APAQ, which are much more tolerant to high operating temperatures.

The 5VSB circuit uses a PS1045L SBR on its secondary side, and the standby PWM controller is an On-Bright OB5282 IC. Once the PSU starts, the 5VSB rail takes power from the 5 V rail. This is done through a change-over switch, a Sync Power SPN3006 FET.

There are lots of polymer caps on the modular board's face.

Soldering quality is excellent.

The supervisor IC is a Weltrend WT7527RT. There is also an LM393G dual differential comparator, which is most likely used by the protection features circuit.

The cooling fan is a be quiet! BQ QF2-12025-MS. It has a diameter of 120 mm and uses a rifle bearing.
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