Introduction

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. In a previous review, I evaluated the strongest model of the line, and in today's review, we will take a look at the 650 W variant. The 650 W Gold competition includes the new Corsair RM650x (2021) with the Magnetic Levitation fan, XPG Core Reactor 650, and Seasonic GX-650. The Super Flower Leadex III Gold is also a strong competitor, but the Leadex V has replaced the line. Unfortunately, Super Flower hasn't sent me any Leadex V samples thus far.

All Pure Power 11 FM (Fully Modular) units are made by CWT, while the other non-modular and semi-modular Pure Power units use FSP platforms. This new CWT platform is only available to be quiet!. It is also a top performer that doesn't cost a bomb, which has the new Pure Power models achieve high performance-to-price ratios.

The 650 W Pure Power FM unit is fully compliant with the ATX12V v2.52 specification, so it is very efficient under incredibly light and light loads. On top of that, it is compatible with Microsoft's Modern Standby mode if you find a compatible mainboard. Its cooling is handled by a 120 mm SilentWings fan driven by a highly relaxed fan-speed profile. Lastly, it is rated for up to 40°C continuous full-power delivery.

Specifications

12V2 should be stronger since it has both EPS and two PCIe connectors.

Photos

With no vivid colors or fancy design elements, but, rather, a somber, serious approach, this is a typical be quiet! box.


I would like to see some packing foam inside the box for better protection. Most DOAs are due to bad shipping conditions.


I also mentioned this in the Pure Power FM 750 W review: I like the fan's white accents. Such small details make some products stand out from the crowd, although the exterior design is not as important with PSUs.


The power specifications label almost entirely covers one of the PSU's sides.


The modular panel has the same ten sockets as the 750 W model.


160 mm deep, you cannot call this PSU large.

Cables and Connectors

All but the ATX cable are black and flat—the ATX cable is fully sleeved, though. The cables are also sufficiently long. If you install this PSU into a full-tower chassis, you might run into problems with the EPS cables, but higher-capacity PSUs are normally used in such large cases.


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.



This is a new CWT platform made for be quiet!. The design is clean, allowing for good airflow between components, which are nicely spread across and not installed right next to each other. The heatsinks are pretty large for a CWT platform, and typical of the secondary side, there are no heatsinks since the +12 V FETs are installed on a daughter-board.


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 if a high power surge destroys it.


The NTC thermistor and bypass relay combination is for suppressing large inrush currents. It doesn't do a great job, though.


The single bridge rectifier is bolted to a beefy heatsink.


ON Semiconductor provides the FETs used in the APFC converter. The same goes for the boost diode. The only downside here is the selection of the low-end Teapo bulk caps with a temperature rating of 85 °C. These are at least large capacity bulk caps to ensure a hold-up time of over 17 ms.


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


The main FETs are installed in a half-bridge topology.


The LLC resonant controller is a Champion CU6901VAC.


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


The FETs that regulate the +12 V rail are four On Semiconductor NTMFS5C430Ns, while the 750 W unit uses six of those. They are installed on a vertical board close to the main transformer.


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 Pure Power 11 FM 750 W and Corsair RM850x (2021) PSUs.


To keep the cost as low as possible, Teapo and Elite provide the electrolytic caps. I'm not too fond of the Teapo SC caps because of their low lifetime. Like the 750 W model, 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.


Polymer caps cover the face of the modular PCB.


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. The same fan is used in the 750 W model.