be quiet! SFX L Power 600W PSU Review

Early Verdict

The new be quiet! SFX-L offerings are interesting since they manage to combine good performance levels along with a silent operation, something that isn't common in the small form factor PSU categories. With a little lower price and a 5-year warranty, the SFX L Power 600W will be much more competitive though.


  • +

    Full power at 46°C

  • +


  • +

    Load regulation

  • +

    In spec hold-up time

  • +

    Accurate Power Ok signal

  • +


  • +

    Fully modular

  • +

    Full protections set

  • +

    FDB fan (with a single gasket though)

  • +

    4x PCIe connectors

  • +

    Compact dimensions


  • -


  • -


  • -

    Inrush current

  • -

    OPP is set high

Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Features & Specifications

With High Power's help, be quiet! recently joined the SFX-L market with one 500W model and a 600W version. Previously, the company only had two small form factor options available, so these latest PSUs double its reach.

SFX-L is preferred in many compact cases because it accommodates a fan as large as 120mm, enabling adequate airflow at lower speeds. Thus, it offers much lower noise output than power supplies sporting 80mm and 92mm fans.

Today's review covers the higher-capacity SFX L Power 600W. It's 80 PLUS Gold-certified, while on the Cybenetics scale it achieves ETA-A (88-91%) and LAMBDA-A- (25-30 dB[A]) ratings. be quiet!'s SFX L Power 500W shares the same ETA rating, but generates less noise, allowing it to land in LAMBDA-A+ (20-25 dB[A]) territory.

According to be quiet!, the SFX L Power 600W is suitable for mini-ITX and compact gaming systems. Given four PCIe connectors and 600W of capacity, it's indeed able to support a capable gaming PC. However, the single EPS connector will surely limit compatibility with high-end mainboards.

The platform that High Power built for be quiet! is modern. It uses an LLC resonant converter on the primary side, along with synchronous rectification on the secondary side and DC-DC converters for generating the minor rails.


be quiet! employs fully modular cabling, which is the de-facto standard for high-end PSUs nowadays. Because of its SFX-L form factor, though, this unit can only deliver full power continuously at up to 40°C ambient. Of course, we'll push harder than that during our benchmark suite and see how the SFX L Power 600W responds.

A comprehensive list of protections features only lacks OCP for the +12V rail. However, in single-rail models like this one, over-power protection serves that purpose instead.

The 120mm cooling fan utilizes a fluid dynamic bearing, facilitating quiet operation and increased reliability. In fact, it offers a similar lifetime as double ball-bearing fans under normal environmental conditions. There is no semi-passive mode. But as long as the fan spins slowly under light and moderate loads, this won't be a problem. We actually prefer it, since heat doesn't build up inside of the PSU.

Three years of warranty coverage sounds pretty weak compared to other small form factor power supplies with longer guarantees. be quiet! needs to provide a five-year warranty, at least.

Power Specifications

Swipe to scroll horizontally
Max. PowerAmps22225030.3
Total Max. Power (W)600

The +12V rail can deliver up to 50A of current, while the minor rails are strong enough, given their 105W maximum combined power. Moreover, the 5VSB rail is ample in light of this PSU's overall capacity.

Cables And Connectors

Swipe to scroll horizontally
Modular Cables
DescriptionCable CountConnector Count (Total)Gauge
ATX connector 20+4 pin (300)1118AWG
4+4 pin EPS12V (405mm)1118AWG
6+2 pin PCIe (500mm+150mm)1218AWG
6+2 pin PCIe (405mm+150mm) 1218AWG
SATA (500mm+150mm+150mm)1318AWG
SATA (300mm+150mm+150mm)1318AWG
Four-pin Molex (300mm+200mm+200mm)1318AWG

It is great to see four PCIe connectors on an SFX-L PSU. Unfortunately, it seems as though there wasn't enough space on the modular board for a second EPS connector.

Cable length is naturally short, since SFX-L-based PSUs are built for small cases. The distance between connectors is ideal, though. We greatly appreciate the fact that the four-pin Molex connectors are installed 20cm from each other (even if we secretly wish High Power would include at least one more).

Again, compact dimensions prevent be quiet! from including more sockets on the modular panel. However, four connectors on the SATA and four-pin Molex cables could easily give you access to more connectors if needed.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • reghir
    Not sure take a look at NewEgg reviews which show 3 users reporting DOA units
  • AC____
    How does it compare to Corsair's?
  • Aris_Mp
    The SF600 has higher performance. This is shown in the relative performance chart. However in the overall noise score the SF600 is much higher as well, because its fan profile gets highly aggressive once you load its minor rails. In real life conditions where the minor rails are lightly used, it is quite silent.
  • Aris_Mp
    DOA can happen for several reasons, with hard shipping conditions being one of them.
  • expert_vision
    You know what baffles me? How is it possible that no monitoring is offered in today PSUs ? I used to have a HighPower PSU 10 years ago that had a simple 7 segment display, showing instantaneous power draw in watts, and a 3 header pin for FAN RPM. You'd think by today that would be standard. But no, instead they put freaking RGB in everything ...
    Too expensive when you cheap out on a 85C primary cap.
  • below
    I had bought one of them a few weeks ago and after installing in bitfenix portal case it has start to randomly make noises. I had rebuild my block two times just to make sure that there is nothing except PSU fan itself making that noise. The noise is comparably with very old HDD's or even Floppy crunching, its super annoying and only appears in PSU working state (when fan at the bottom) and mostly on high load, also noise could be very loud

    Also I have found some review on Spanish (I think) from amazon about this PSU and customer have exactly the same issue, so looks like it could be design problem.
    This PSU is a winner of most comparisons an reviews everywhere and I very dissapointed that none of reviewers couldn't find such awfull issue for quiet PSU.

    Also it should be a shame for company named 'be quiet' that it's 'silent wings' in that PSU making that horrible noises.