be quiet! Pure Power 11 FM 850 W Review 8

be quiet! Pure Power 11 FM 850 W Review

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

The be quiet! Pure Power 11 line addresses users who want a good PSU at a reasonable price. The line boast a high performance per dollar ratio, and so far, the highest capacity model has had 750 W maximum power output. The 550-750 W FM models of the Pure Power 11 line use CWT platforms, while the CM (semi-modular) is based on the FSP Raider platform, at least for the 700 W unit I evaluated.

Since 750 W are not enough for high-end gaming systems, be quiet! has now added 850 W and 1 kW models to the Pure Power 11 line. These two new units will complete the line, rendering the Pure Power 11 FM models direct competitors to Corsair's popular RMx and RM units. Instead of CWT, be quiet! teamed with HEC for these Pure Power 11 models, so it will be interesting to see how the be quiet! Pure Power 11 FM 850 W model fares against the CWT-made Corsair RM850x.

Compared to the RM850x and RM850, the FM 850 has half the warranty, at five years, and uses an inferior fan with a rifle bearing, as Corsair's offering uses a topnotch ML fan. That said, the ML fan is noisier. The new RM850x has over ten dBA higher average noise output than its predecessor using a rifle bearing fan. Lastly, the FM 850 has two +12 V rails, while the RM850(x) only has one. Several users, including me, prefer single +12 V rail to multi +12 V rail PSUs because chances for shutdowns during power spikes are lower. That said, PSUs with multiple +12 V rails are slightly safer when something goes wrong. However, I have been pushing PSUs to the limit (and beyond) for many years and never encountered a problem that forced me towards multiple +12 V rail designs.


be quiet! Pure Power 11 FM 850W
Features & Specifications
Max. DC Output850 W
Efficiency80 PLUS Gold, Cybenetics Gold (89–91%)
NoiseCybenetics A- (25–30 dBA)
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-HS)
Semi-Passive OperationNo
Dimensions (W x H x D)150 x 85 x 160 mm
Weight1.83 kg (4.03 lb)
ComplianceATX12V v2.52, EPS 2.92
Warranty5 years
Price at Time of Review (excl. VAT)$129.9
be quiet! Pure Power 11 FM 850W
Power Specifications
Rail3.3 V5 V12 V112 V25 VSB-12 V
Max. Power22 A22 A40 A36 A3 A0.3 A
120 W70.8 A15 W3.6 W
849.6 W
Total Max. Power850 W
be quiet! Pure Power 11 FM 850W
Power Distribution
12V1ATX, PCIe (left), Peripheral
Ideally, the EPS and PCIe connectors would not use the same rail, but this PSU only has two +12 V rails, so compromises had to be made.
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Jun 29th, 2022 14:24 EDT change timezone

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