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Enermax Revolution X’t II 750W Power Supply Review

Enermax recently released a successor to the Revolution X't line and the new models are made by CWT, featuring 80 PLUS Gold efficiency, Japanese caps and a quality fan. Today, we're testing the ERX750AWT model.

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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Not only is the hold-up time lower than 17ms, but it matches the power-good hold-up time. Normally, that latter measurement should be at least 1ms lower to let the system shut down before the rails go out of spec. We've seen much worse cases though, where the power-good signal drops when the rails are already out of spec.

The worst part is that, after a couple of test cycles, the PSU stopped working following the explosion mentioned on the previous page. Again, we don't think this is a fundamental issue with the design since the main FETs are strong enough to handle our abuse.

5/1/2016 Update: The second sample finally arrived and this time we didn't encounter any problem switching on and off the PSU during full power delivery. We conducted multiple test cycles and all rolled fine, so apparently the issue that we faced with our first sample was just an isolated incident.

Inrush Current

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

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The inrush current is low with both voltage inputs.

Load Regulation And Efficiency Measurements

The first set of tests reveals the stability of the voltage rails and the PSU's efficiency. The applied load equals (approximately) 10 to 110 percent of the maximum load the supply can handle, 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
14.405A1.974A1.950A0.984A74.7785.23%80530.137.62 °C0.967
12.073V5.071V3.383V5.062V87.7342.32 °C115.1V
29.856A2.958A2.937A1.185A149.7089.68%80530.138.27 °C0.980
12.059V5.061V3.368V5.049V166.9343.27 °C115.1V
315.669A3.465A3.451A1.386A224.8490.98%80530.139.21 °C0.984
12.047V5.053V3.358V5.036V247.1244.77 °C115.1V
421.480A3.963A3.942A1.591A299.6691.09%80530.139.89 °C0.986
12.034V5.043V3.347V5.025V328.9846.99 °C115.1V
526.969A4.968A4.948A1.795A374.6990.92%80530.140.88 °C0.988
12.021V5.034V3.333V5.010V412.1048.64 °C115.1V
632.464A5.973A5.967A1.998A449.5690.41%80530.142.09 °C0.988
12.007V5.022V3.316V4.997V497.2552.06 °C115.1V
737.968A6.988A6.996A2.205A524.5389.03%100036.243.35 °C0.987
11.995V5.012V3.301V4.984V589.1553.96 °C115.1V
843.502A7.999A8.032A2.411A599.4688.21%124043.643.97 °C0.988
11.978V5.001V3.287V4.971V679.5955.44 °C115.1V
949.481A8.514A8.579A2.415A674.5087.37%160047.445.49 °C0.989
11.963V4.990V3.274V4.965V771.9957.65 °C115.0V
1055.435A9.041A9.101A2.520A749.3886.54%160047.445.80 °C0.990
11.945V4.981V3.263V4.953V865.9358.82 °C115.1V
1161.784A9.056A9.124A2.525A824.2385.61%160047.447.10 °C0.991
11.929V4.972V3.254V4.946V962.7361.10 °C115.1V
CL10.099A14.022A14.005A0.004A117.7083.16%80530.143.61 °C0.980
12.069V5.027V3.284V5.057V141.5454.36 °C115.1V
CL261.945A1.002A1.003A1.002A753.5087.34%160047.445.63 °C0.990
11.948V5.018V3.334V5.003V862.7258.17 °C115.0V

Efficiency definitely satisfies the 80 PLUS Gold standard, since even at high ambient temperatures we see numbers that meet the corresponding requirements at 20 and 50 percent load. Moreover, they're only 0.5 percent away from the desired 87 percent mark under full load. The PSU's fan rotates slowly at up to 60 percent load and only hits full speed with 90 to 110 percent of the PSU's max-rated capacity applied. Under normal conditions, we expect this PSU to be very quiet.

Load regulation at +12V is pretty tight. At 5V and 5VSB it's satisfactory, while at 3.3V it's loose. Fortunately for Enermax, this rail is of secondary importance.

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