be quiet! Power Zone 850 W Review 4

be quiet! Power Zone 850 W Review



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

be quiet! products are not that easy to find in the US, but we believe that the company is hard at work to expand into the region since there are plenty of potential buyers there. be quiet! has already established itself in Europe, especially Germany, and they definitely are among the top choices for noise-sensitive users when it comes to both PSUs and cooling products (e.g. fans and heatsinks/coolers).

We tested the Power Zone 1000 W a while ago and were left quite satisfied by its performance, but the time has come for the second unit in command of the Power Zone line, the Power Zone 850 W, to be put to the test. Like its big brother, this one is also 80 Plus Bronze compliant while featuring a fully modular cabling design and a high-quality SilentWings fan. be quiet! even provides the option to connect up to three case fans directly to the PSU for reduced noise output and optimized system cooling, since these fans will be thermally controlled by the PSU itself. Like all Power Zone units, this one features the Cool Off function which operates the fan for three minutes after the system shuts down to cool down all sensitive PSU components, which prolongs their lifetime. This isn't the first time we see such a feature in a PSU, but we haven't seen one engage the fan for such a long time after the system shuts down. Finally, like all modern PSUs, the Power Zone 850 W supports the Deep Power Down modes that were introduced with Intel’s Haswell CPUs (C6 & C7 sleep states).


be quiet! Power Zone 850W Features & Specs
Max. DC Output850W (900W Peak)
Efficiency80 PLUS Bronze
Intel Haswell ReadyYes
Operating temperature0°C - 50°C
ProtectionsOver Voltage Protection
Under Voltage Protection
Over Power Protection
Over Temperature Protection
Over Current Protection
Short Circuit Protection
Cooling135 mm Fluid Dynamic Bearing Fan (SilentWings)
Semi-passive operationNo
Dimensions150 mm (W) x 86 mm (H) x 175 mm (D)
Weight2.0 kg
ComplianceATX12V v2.4, EPS 2.92
Warranty5 years
Price at time of review (exc. VAT)$159.99
Efficiency is officially Bronze; however, as we saw with the Power Zone 1000 W, be quiet! was rather conservative with the efficiency certification they acquired. We still don't understand why since the aforementioned unit could easily clear the Gold certification, and we are pretty sure the same will apply to the 850 W unit. Contrary to the efficiency certification, its other characteristics are topnotch since it features a fully modular cabling design, is Haswell ready, comes equipped with all available protection features, and has a maximum operating temperature of 50°C, which is in line with the ATX specification. be quiet! even equipped the unit with a high quality Fluid Dynamic Bearings (FDB) fan. FDB fans are considered the best in the industry. The PSU is quite long at 17.5 cm; however, every ATX-compliant chassis will house it without any problems, and it is, as you can see, listed as ATX v2.4 compatible, which is the most recent ATX spec. Its price looks and is very high for a Bronze unit, at least on papers, while the provided warranty is long enough at five years.

be quiet! Power Zone 850W Power Specs
Max. Power25A25A70A3A0.3A
Total Max. Power850W
The unit can deliver most of its power on the +12V rail alone, and the minor rails are too strong for today's PCs since they hardly utilize them. The 5VSB rail can deliver enough power to easily handle any system this PSU will have to power.

Cables & Connectors, Power Distribution

Modular Cables
ATX connector (600mm)20+4 pin
8 pin / 4+4 pin EPS12V (700mm)2
6+2 pin PCIe (550mm)4
SATA (550mm+150mm) / 4 pin Molex (+150mm+150mm) / FDD (+150mm)2 / 2 / 1
SATA (550mm+150mm+150mm+150mm)4
SATA (550mm+150mm+150mm)3
4 pin Molex (550mm+150mm+150mm+150mm)4
Fan Connectors (750mm)3
There are enough connectors for the capacity of this unit; however, we have seen several 850 W units with six PCIe connectors. Cable length is adequate and the distance among connectors is sufficiently large; some might even prefer SATA connectors that are a little closer to one another.

The 24-pin ATX connector is mostly equipped with 18AWG wires, though we spotted some 20AWG and very few 22AWG wires. The latter are used for voltage sense purposes, hence their smaller thickness. The EPS and PCIe connectors use thicker 16AWG gauges, while all others use standard 18AWG wires.

Since this PSU features a single +12V rail, we have nothing to comment on when it comes to its power distribution.


The box is pretty large and be quiet!'s logo, although small, easily stands out because of the font's distinctive color. The face of a PSU's package usually holds the corresponding 80 Plus certification badge, but be quiet! chose not to parade it around since this unit is only Bronze certified, although its price puts it up against the Gold-certified competition.

On this side, we find a features description in French and Portuguese.

Here is a useful schematic of all available connectors along with their cable length.

The back of the package holds a photo of the PSU that highlights its three crucial features: The fully modular design, its Cool Off function of the fan, and the high quality SilentWings fan. You will also find the power-specifications table and a features description in two languages, English and German, here.

Near the bottom-left corner are a series of badges, including the 80 Plus Bronze badge, and a list of various awards be quiet! earned from various review sites, including TPU's Recommended award, can be found on the obverse side.


The contents of the box are nicely arranged, and the PSU comes inside a nice cloth bag.

The modular cables are tied together by three Velcro straps, and the rest of the bundle consists of an AC power cord, the user's manual, enough zip ties, and a set of fixing bolts.

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