be quiet! SFX L Power 600W PSU Review

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Final Analysis

At long last, be quiet! is active in the SFX-L market. This form factor combines compact dimensions and notably less noise than standard SFX, since it can accommodate 120mm (rather than just 92mm) fans. Moreover, the smaller a PSU's platform, the more difficult it becomes to cool down effectively. Crowded PCBs restrict airflow, after all. And this problem gets worse as capacity increases. So naturally, SFX-L-based power supplies enjoy a big advantage over SFX ones. Since mini-ITX cases aren't compatible with the larger ATX PSUs most commonly found in desktop PCs, SFX and SFX-L are critical in enabling compact systems.

The cooperative effort between be quiet! and High Power looks interesting enough: the OEM has plenty of experience designing and manufacturing high-density PSUs, while be quiet! enjoys a great reputation in the quiet computing market. The resulting platform in be quiet!'s SFX-L models doesn't offer ground-breaking performance, but it fares well in our benchmarks and, on top of that, is efficient. Thanks to the SFX L Power 600W's 120mm fan, high efficiency, and optimized fan profile, overall noise is low at normal ambient temperatures. Even under stressful conditions, when the temperature rises over 45°C, the fan's noise remains reasonable. Obviously, be quiet! paid a lot of attention to this model's acoustic footprint, and the outcome is excellent. So far, only FSP's SFX-based SDA600 is quieter.

In the performance section, load regulation and efficiency are in line with our expectations, and we appreciate the fact that all protection features are present. We would like to see a lower over-power protection triggering point, since 810W is pretty aggressive for such a compact platform. This power level might be feasible under normal operating temperatures. However, in warmer environments, the PSU's components endure much more stress, reducing their useful life. Thankfully, over-temperature protection is set at a normal level, so that should effectively protect the PSU.

When it comes to ripple suppression, we aren't fully satisfied. We would like to see lower ripple at +12V and 3.3V. Moreover, the lack of an NTC thermistor is a huge disappointment since it allows for very high inrush currents during the PSU's start-up phase. We suspect that improving the 5VSB rail's efficiency was justification for the NTC thermistor's omission; when the PSU operates normally, you can bypass this thermistor with a relay, but that isn't an option in standby.

With a price tag around $120, be quiet!'s SFX L Power 600W is an expensive power supply in a competitive market. If the company wants a larger share of the SFX-L pie, it'll need to make this model more affordable and extend its warranty to five years, if possible. One of the biggest problems with long warranties is their relationship to cooling fan choice. The SFX L Power 600W employs an FDB-based fan. However, we only found a single gasket and not two, meaning that its lubricant will evaporate sooner compared to higher-quality alternatives. Given the lack of a semi-passive mode as well, this might be the reason for be quiet!'s three-year warranty. 

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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.