be quiet! SFX L Power 600W PSU Review

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.

Load Regulation, Hold-Up Time & Inrush Current

To learn more about our PSU tests and methodology, please check out How We Test Power Supply Units. 

Primary Rails And 5VSB Load Regulation

Load Regulation testing is detailed here.

Hold-Up Time

Our hold-up time tests are described in detail here.

The hold-up time is right where it should be. And although the power-good signal is a little shorter than the ATX spec's recommendation, it's still accurate, which is what matters most.

Inrush Current

For details on our inrush current testing, please click here.

The lack of an NTC thermistor leads to very high inrush currents. High Power should make the necessary changes to this platform as soon as possible!

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the SFX L Power 600W's efficiency. The applied load equals (approximately) 10 to 110 percent of the PSU's maximum load in increments of 10 percentage points.

We conducted two additional tests. During the first, we stressed the two minor rails (5V and 3.3V) with a high load, while the load at +12V was only 0.1A. This test reveals whether a PSU is compatible with Intel's C6/C7 sleep states or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedFan NoiseTemps (In/Out)PF/AC Volts
13.117A1.974A1.954A0.996A59.78783.863%1400 RPM27.3 dB(A)38.14°C0.972
27.260A2.968A2.938A1.199A119.81388.488%1435 RPM28.6 dB(A)38.70°C0.992
311.752A3.478A3.446A1.400A179.88589.971%1455 RPM29.5 dB(A)38.95°C0.995
416.250A3.975A3.935A1.607A239.76190.528%1550 RPM30.2 dB(A)39.17°C0.997
520.419A4.980A4.932A1.816A299.77590.480%1560 RPM30.4 dB(A)39.79°C0.998
624.585A5.987A5.931A2.020A359.73590.148%1610 RPM31.3 dB(A)40.24°C0.998
728.755A7.009A6.939A2.231A419.74189.657%1655 RPM32.2 dB(A)41.27°C0.999
832.928A8.023A7.956A2.445A479.67489.069%1765 RPM34.2 dB(A)42.46°C0.999
937.532A8.534A8.484A2.445A539.71088.458%1830 RPM34.9 dB(A)43.70°C0.999
1041.890A9.063A8.995A3.084A599.66287.718%1860 RPM35.4 dB(A)44.83°C0.999
1146.829A9.071A9.014A3.090A659.59386.965%1870 RPM35.6 dB(A)46.07°C0.999
CL10.098A13.019A13.003A0.004A110.01881.865%1790 RPM34.5 dB(A)44.20°C0.993
CL249.948A1.005A1.002A1.002A622.14388.269%1850 RPM35.2 dB(A)44.58°C0.999

Load regulation on every rail except for 5VSB is pretty tight, and the PSU has no problem delivering more than its full power at high ambient temperatures.

That FDB fan spins quickly throughout our benchmark session, but its noise output isn't annoying, even during the full load and overload tests. Moreover, the SFX L Power 600W satisfies the 80 PLUS Gold efficiency requirements, despite our elevated ambient temperatures. Finally, we notice high power factor readings, meaning less energy goes wasted.

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.