Be quiet! Pure Power 11 FM 550W power supply review

Be quiet! developed a unique platform with Channel Well Technology for its Pure Power 11 FM range, and the results are fantastic. The Pure Power 11 FM with 550W capacity is our top pick for this power category, which is why it’s one of the best power supplies for gaming. (opens in a new tab)and it’s ideal for low-demand systems where users need a premium PSU under $100.


Manufacturer (OEM) Channel well technology
Max. DC output 550W
Efficiency 80 PLUS Gold, Cybenetic Gold (87-89%)
Noise Cybenetics A (20-25 dB[A])
Modular Yes (fully)
Intel C6/C7 power state support Yes
Operating temperature (continuous full load) 0 – 40°C
Protections OVP, UVP, OPP, OCP, OTP, SCP, Surge
No load operation Nope
Cooling 120mm Rifle Bearing Fan (BQ QF2-12025-MS)
Semi-passive operation Nope
Dimensions (W x H x D) 150x85x160mm
lester 1.56 kg (3.44 lbs)
Form factor ATX12V v2.52, EPS 2.92
guarantee 5 years
Price $90

The PSU is 80 PLUS Gold and Cybenetics Gold certified in efficiency and has a Cybenetics A noise rating, proving it’s quiet. The dimensions are standard, with a depth of 160 mm, and the cooling fan uses a rifle bearing for increased reliability. The five-year warranty is half of what the competition offers (eg Corsair, RM550x). Still, you can’t call it short.

The CWT platform has good welding quality in general. Our main objection is to bulk 85C caps when the competition uses 105C caps. Secondary side Elite caps are the best alternative to Japanese caps, which are hard to find these days and very expensive. Finally, the low speed uses a rifle bearing, so it will have no problem surviving the warranty (and then some).

Rail 3.3V 5V 12V1 12V2 5VSB -12V
Max. Power (Amps) 20 20 28 24 3 0.3
Max. Power (Watt) 120 120 550 550 15 3.6

There are two 12V rails which can deliver up to 550W combined, while the minor rails can go up to 120W. The standby rail is also strong enough, with a current output of 3 A max.

Cable Amount included Caps integrated into the cable
20+4 pin ATX connector 1 Nope
4+4 pin EPS12V 1 Nope
PCIe 6+2 pin 2 Nope
SATA 2 Nope
SATA / 4 pin Molex / FDD 1 Nope
Mains power cord 1 N / A

The ATX cable could be a bit longer. The same goes for the single EPS cable. It would also be nice to have an EPS connector and an ATX12V connector instead of a single EPS. Both PCIe connectors are on dedicated cables, so everything is fine there, the distance between all peripheral connectors is adequate, and the FDD connector could be replaced with a 4-pin Molex to bring their number to three.


The 12V load regulation is satisfactory and tight on the other rails, and the ripple suppression is excellent!

The hold time is well over 17ms, which the ATX spec requires, and the power ok signal hold time is close to 16ms. The inrush current is low with 115V and high with 230V.

It must be said that this is a very efficient platform: the 5VSB rail has decent efficiency and the vampire power is low. Average efficiency is high, even for a Gold rated unit.

Transient response voltage deviations are kept low on all rails and the PWR_OK delay is in the region of 100-150ms, so the PSU supports the low-power alternate modes recommended by the specification ATX.

The OCP trigger point on the first 12V rail is high and very high on the second. Having a highly defined OCP makes sense in low capacity PSUs to avoid power spike issues, given that the rig can handle such high power loads. The overpower protection, on the other hand, is set conservatively. In general, it is not ideal to overload your diet. If you need more power, get a more powerful power supply.

As for noise, the Be quiet! honors its brand name, staying silent, but the Corsair RM550x (2021) does even better here.

Final Thoughts

Be quiet!  Pure power 11 FM 550W

(Image credit: future)

Be quiet! has a long history in the manufacture of silent products and power supplies, among others. This brand may not be so popular in the US market, which is one of the key players, but it is trending in Germany, its country of origin and with products like the Pure Power 11 FM 550 it will not be difficult to win around the world. popularity soon.

The Pure Power 11 FM 550 showed no problem against intense competition from Corsair, Seasonic, EVGA, Cooler Master and others.

Alan A. Seibert