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Super Flower Leadex Gold 550W PSU Review

Super Flower has made quite an impact on the PSU market. Its Leadex platform enjoys huge popularity, both under SF's brand name and other companies like EVGA. The newest Leadex Gold-rated PSU with 550W capacity is on our test bench today.

Load Regulation, Hold-Up Time And 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.

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Hold-Up Time

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

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The hold-up time tests don't go well. Not only is the measured hold-up less than 16ms (the ATX spec's minimum), but the Power_OK signal drops after, and not before, the PSU's rails go out of spec. This means that your motherboard gets a false power-good signal from the PSU. Indeed, we measured the +12V rail floating at around 10.8V when Power_OK dropped to zero. This is a very low voltage level that applies lots of stress to the voltage regulators of components fed by +12V.

In a high-end PSU like this one, we didn't expect such nasty behavior. We have to admit that we're very disappointed by Super Flower's decision to drop the power-good signal so late, which is probably done to give the false impression that the hold-up time lasts longer. By the end of our review, this is going to cost to this PSU a lot of performance points. Whereas it might have received an award for performance, there's no way it will now.

Inrush Current

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

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The measured inrush current was normal with both inputs (115V and 230V).

Load Regulation And Efficiency Measurements

The first set of tests explores voltage rail stability and efficiency. The applied load equals (approximately) 10 to 110 percent of the supply's maximum 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 0.10A. This test reveals whether a PSU is Haswell-ready or not. In the second test, we determined the maximum load the +12V rail could handle with minimal load on the minor rails. 

Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan Speed (RPM)Noise (dB[A])Temps (In/Out)PF/AC Volts
12.693A1.988A1.990A0.983A54.7683.30%0048.73 °C0.950
12.321V5.026V3.316V5.075V65.7447.34 °C115.0V
26.411A2.979A2.984A1.186A109.7687.45%110040.737.60 °C0.968
12.307V5.023V3.315V5.062V125.5142.53 °C115.0V
310.482A3.486A3.499A1.384A164.8988.91%106038.337.69 °C0.980
12.289V5.020V3.313V5.050V185.4542.76 °C115.0V
414.546A3.983A3.984A1.585A219.7689.58%108039.739.02 °C0.986
12.278V5.018V3.312V5.037V245.3245.13 °C115.1V
518.282A4.978A4.982A1.791A274.7589.67%111040.939.88 °C0.989
12.269V5.014V3.310V5.023V306.3947.10 °C115.1V
622.017A5.983A5.984A1.996A329.7489.47%114039.840.74 °C0.991
12.262V5.010V3.308V5.008V368.5549.20 °C115.1V
725.760A6.993A6.986A2.199A384.7588.88%116538.741.75 °C0.992
12.254V5.007V3.306V4.993V432.9151.54 °C115.1V
829.501A7.994A7.989A2.407A439.6888.37%123040.442.77 °C0.993
12.247V5.004V3.304V4.979V497.5554.07 °C115.1V
933.685A8.497A8.509A2.410A494.7787.70%126039.644.01 °C0.994
12.237V5.000V3.302V4.973V564.1856.72 °C115.1V
1037.607A9.010A9.001A3.032A549.6687.03%132540.745.84 °C0.994
12.230V4.998V3.300V4.943V631.5859.43 °C115.1V
1142.136A9.012A9.005A3.036A604.6486.38%137042.447.19 °C0.994
12.221V4.994V3.298V4.938V699.9762.96 °C115.1V
CL10.100A13.015A13.005A0.004A109.5681.42%131040.045.24 °C0.970
12.333V5.008V3.316V5.084V134.5649.73 °C115.1V
CL245.792A1.002A1.003A1.002A572.5487.71%131040.046.85 °C0.994
12.211V5.008V3.301V5.035V652.7961.08 °C115.1V

Load regulation is super tight on all rails except for 5VSB, which isn't particularly important as long as it meets the ATX specification's requirements. We also noticed that Super Flower improved this PSU's semi-passive mode. The fan doesn't stay inactive for long, compromising the lifetime of heat-sensitive components like electrolytic capacitors.

Since this PSU doesn't exclusively use Japanese capacitors, we were relieved to see the fan spinning during the 20 percent load test. Once the fan is engaged and the temperature is high, you will probably hear it, especially if you are sensitive to noise. On top of that, we noticed some bearing and vibration noise thanks to our super-sensitive sound analyzer (not our ears). This is why, in some of our measurements, we got higher noise levels compared to readings where the fan was actually spinning faster.

The PSU clears the 80 PLUS Gold spec's 20 percent and full load requirements by registering over 87 percent efficiency, However, it falls a little short in the 50 percent load test. Nonetheless, we give it a pass since we conduct our tests in much higher temperatures than the 80 PLUS organization. In general, this unit fares admirably, but it definitely isn't among the most efficient Gold-rated PSUs we've ever tested.

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