Be Quiet! Pure Power 11 FM 850W full review


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The German brand Be Quiet! does it again with their best power supply releases, this time with the powerful Be Quiet! Pure Power 11 FM 850W unit that only falls short to the 1000W upcoming model. This version is meant to be installed on super quiet (pun intended) builds courtesy of its 120mm fan with thermal control and it is manufactured with the brands long standing quality implemented on all their products.



For this model, maximum stability is guaranteed by the 12V double rail delivery provided for the 850W, also being 80 plus gold certified, it provides 93% efficiency margins by using LLC and SR systems. Although a cybernetics analysis is pending, we are almost sure this unit will be getting its gold certification soon as well as a great Lambda score if we base it off the 750W unit’s results. 

Out of the box 

Upon arrival, the box for the Be Quiet! Pure Power 11 FM 850W immediately stands out for its on-brand elegant and meek all black packaging, complete with depictions of the unit’s full modular capabilities and specifications on the back side. Inside, we will find the unit resting on a cardboard stand and protected by bubble wrap, on a separate bag we will also find all the cables for the unit. Additionally, the list of contents is as follows: power supply case for the Be Quiet! Pure Power 11 FM 850W, European plug cord, eight supplementary connection cables and the instruction manual with our guarantee card.

External specs

In terms of design, the brand keeps their style line with a black metallic casing, measuring 160mm x 150mm x 86mm (LxWxH) in total. It seems that spacing is not an issue for any ATX standard casing. When seen from the sides, we immediately notice how the logo was purposely placed sideways in order to be seen when installed, but this leaves the front face free of visuals. 

BeQuiet! Pure Power 11 FM 850W

Now, the fan is the trendsetter for this model as the airflow zone encases the 120mm fan in a white rimmed ring that somehow hides the casing and its in turn lined with rounded black beams in a parallel-type distribution. This type of design makes it a blessing in disguise, as it allows for the fan to be accessed for ease of cleaning just by removing the external screws that keep the grid in place, none of these actions will void the warranty whatsoever. 

On the back panel in turn, the powering setup and connectors are displayed with the usual three pin power entry of 230V and the power on switch that does not have a passive mode, meaning the system will always be active using PWM control on the fan. There is also a beehive rack exhaust for the hot air outflow. The last zone, frontal panel, is embellished with the distinctive vertically arranged modular set up for maximum structure flexibility. 

Cable setup

Pure Power cables are well known for their flat design on all connectors, but the ATX cable, as this one continues having its customary cylindrical shape with metallic mesh, this is due to the bulk of the cables handled and to avoid them from dispersing. The fact that none of the cables use capacitors is noteworthy as this helps with handling and routing. 

Be Quiet! Pure Power 11 ports

The distribution for the cables is as follows: four PCIe connectors with two 16 AWG cables, two 18 AWG CPU connectors, and ten 18 AWG SATA connectors, two Molex ports and just one FDD connector in the eventuality someone still uses those. This version of the Be Quiet! Pure Power 11 FM 850W mixes the SATA, Molex and FDD in one cord to maximize construction of the unit, something not so pleasing for the users, but since rarely something besides SATA is used, this does not become an issue on itself. Overall, none of the cables might pose resistance or shortage on full tower casings, although the ATX cable might seem a bit short with its 550 mm of longitude when installed on unconventional builds. 

Rail distribution

In order to provide optimal levels of stabilization and sustained power, the Be Quiet! Pure Power 11 FM 850W is a multi-rail power supply like its predecessors, which ultimately plays in favor of the user as it offers more security and better hardware. For the voltage and amperage distribution we can consult the back label as well and the user manual, where it will show the power allowance of each connector setting. 

Briefly, we can observe how the build sets 40A to the ATX connector, all three SATA/Molex/FDD connectors and one PCIe set, consisting of the rail 12V1. Rail 12V2 hosts the remaining PCIe port and the two P8 for the CPU connectors with a total of 32A for these conductors. This being said, we can do a quick math and deduct that rail 12V1 will have a total of 480W while 12V2 will power 432W. Although these numbers are theoretical, since the values are shared between both rails respectively for a total of 850W. 

Be Quiet! Pure Power 11 FM 850W review

Internal components 

Taking a look deep inside the Be Quiet! Pure Power 11 FM 850W internal components, we notice right away that although CWT (associated with Be Quite since 2019) is responsible for the PCB build, it is a model specifically designed for Be Quite! Brands name included on it and everything. We are glad to notice that the topology used in this Pure Power FM 11 model is the recent and widely used Resonant Converter and Synchronous Rectifier technology, plus a direct current to direct current technology as well. 

When powering up the unit, you might notice the distinctive click sound produced by the SIP protection system that can be found next to the main capacitors, the NTC thermistors and one metal-oxide varistor. 

Be Quiet! Pure Power 11 FM 850W label

A thorough inspection of the internal components will also show a set of Teapo LH, Taiwanese capacitors of great quality when referenced against the ones used in older versions, welding implementations of exquisite finish and a Weltrend WT752RT supervising system to protect the unit effectively. 

Last but not least, the Be Quiet! Pure Power 11 FM 850W 120mm fan is most likely a Pure Wings model, with grooved wings to ensure air flow through its 2000 RPM regime that will keep all internal components cool to maintain peak performance. Although the normal working regime will be around 1000 to 1300 RPM, it does include a thermal control to regulate the RPM’s as needed for the system to be cool at all times. 


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