Component Analysis

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This is a new platform by HEC, made under the supervision of be quiet!'s PSU PM. Contrary to CWT's designs, the heatsinks are large to allow for higher heat dissipation and lower noise output. Despite the large heatsinks, there is ample space between parts for better airflow. The normal-sized PCB also plays a crucial role here. Soldering quality is good, but I disagree with the caps choice on the secondary side. The Corsair RM850x uses Japanese caps and RM850 quality Elite caps, while be quiet! went with mainstream Teapo caps. The price difference between the FM 850 and RM850x should be more than $20 to justify using Teapo caps, and there is also the RM850 currently being sold at $125, $5 less than the FM 850's MSRP.


The transient filter starts on the AC receptacle and continues on the main PCB.


A Metal Oxide Varistor (MOV) handles voltage surges, while an NTC thermistor suppresses large inrush currents. A bypass relay supports the latter.


The bridge rectifiers can handle up to 30 A of current combined.


The APFC converter uses three Infineon FETs and a CREE boost diode. The bulk caps are by Teapo and offer 780uF combined capacity. They are rated for 2,000 h at 105 °C, so they are pretty good on paper. That said, I would prefer Chemi-Con or Rubycon caps here.


The APFC controller is a Champion CM6500UNX, supported by a CM03AX IC.


The two main switching FETs are installed in a half-bridge topology, and an LLC resonant converter is used for higher efficiency. The resonant controller is a Champion CM6901T6X.


The main transformer is next to the resonant tank and capacitive parts of the LLC resonant converter.


Six Hunteck FETs regulate the +12 V rail. They are installed on the solder side of the main PCB. Three heatsinks above these keep operating temperatures under control.


Under normal operating temperatures, the electrolytic filtering caps most likely won't have a problem outliving the provided warranty. Still, I would like to see higher-quality electrolytic caps. Many polymer caps are also used.


Two DC-DC converters generate the minor rails.


The supervisor controller is a Weltrend WT7527RT.


The standby PWM controller is an EM8569D. The rectifier on the low side is a PS1060L SBR.


Several polymer and electrolytic caps at the face of the modular panel form an extra ripple-filtering layer.


Soldering quality is pretty good.


The cooling fan is by be quiet!, and its model number is QF2-12025-HS. It uses a rifle bearing, which will have it last for quite a while.