Enermax D.F. 500W PSU Review

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.

Hold-Up Time

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

Despite a small bulk cap, the EPF500AWT's hold-up time easily exceeds 17ms, satisfying the ATX spec. The power-good signal also lasts more than 16ms, and it's accurate, dropping before the rails go out of spec.

Inrush Current

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

Measured inrush current is quite high, given the PSU's moderate capacity.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the EPF500AWT'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 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
Fan Noise
Temps (In/Out)PF/AC Volts
12.323A1.973A1.963A0.976A49.77686.006%580 RPM
20.8 dB(A)
25.679A2.958A2.952A1.177A99.75890.413%580 RPM20.8 dB(A)38.46°C0.963
39.384A3.465A3.470A1.376A149.91491.522%580 RPM20.8 dB(A)39.29°C0.972
413.081A3.963A3.959A1.576A199.76891.853%600 RPM21.4 dB(A)39.20°C0.973
516.445A4.970A4.964A1.781A249.78791.768%720 RPM24.5 dB(A)39.58°C0.976
619.806A5.971A5.975A1.985A299.70091.446%920 RPM31.7 dB(A)40.27°C0.981
723.178A6.981A6.990A2.191A349.72991.042%930 RPM32.1 dB(A)41.48°C0.985
826.542A7.991A8.013A2.396A399.65489.748%940 RPM32.3 dB(A)41.99°C0.990
930.346A8.502A8.558A2.402A449.68289.381%940 RPM32.3 dB(A)42.92°C0.992
1034.101A9.028A9.064A2.504A499.56488.876%940 RPM32.3 dB(A)43.77°C0.994
1138.249A9.038A9.080A2.512A549.57388.290%940 RPM32.3 dB(A)44.78°C0.995
CL10.099A12.011A12.003A0.005A101.67486.913%940 RPM32.3 dB(A)43.57°C0.966
CL240.958A1.003A1.001A1.003A508.57789.619%940 RPM32.3 dB(A)44.27°C0.994

Load regulation at +12V is tight, and it's merely satisfactory on the other rails. The fan's noise remains at low levels, even when we push the PSU to its limits (and above them). Enermax's fan does a fine job, given the large temperature deltas that our equipment recorded.

As for efficiency, the EPF500AWT clears our 20% load test easily. It also comes close to the 80 PLUS Platinum certification's requirements in the 50% and 100% load tests. After all, 80 PLUS tests at a very low ambient, so it's natural to see worse results when we test at more realistic temperatures.

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