Test Setup

All measurements were performed using two Chroma 6314A mainframes equipped with the following electronic loads: six 63123A [350 W each], one 63102A [100 W x2], and one 63101A [200 W]. The aforementioned equipment is able to deliver 2500 W of load, and all loads are controlled by a custom-made software. We also used a Rigol DS2072A oscilloscope kindly sponsored by Batronix, a Picoscope 3424 oscilloscope, a Picotech TC-08 thermocouple data logger, two Fluke multimeters (models 289 and 175), and a Yokogawa WT210 power meter. We also included a wooden box, which, along with some heating elements, was used as a hot box. Finally, we had at our disposal three more oscilloscopes (Rigol VS5042, Stingray DS1M12, and a second Picoscope 3424), and a Class 1 Bruel & kjaer 2250-L G4 Sound Analyzer which is equipped with a type 4189 microphone that features a 16.6 - 140 dBA-weighted dynamic range. You will find more details about our equipment and the review methodology we follow in this article. We also conduct all of our tests at 40°C-45°C ambient to simulate the environment seen inside a typical system with a higher accuracy, with 40°C-45°C being derived from a standard ambient assumption of 23°C and 17°C-22°C being added for the typical temperature rise within a system.

Primary Rails Load Regulation

The following charts show the voltage values of the main rails, recorded over a range from 60 W to the maximum specified load, and the deviation (in percent) for the same load range.

5VSB Regulation

The following chart shows how the 5VSB rail deals with the load we throw at it.

Hold-up Time

Hold-up time is a very important PSU characteristic and represents the amount of time, usually measured in milliseconds, a PSU can maintain output regulations as defined by the ATX spec without input power. In other words, it is the amount of time the system can continue to run without shutting down or rebooting during a power interruption. The ATX specification sets the minimum hold-up time to 16 ms with the maximum continuous output load. In the following screenshot, the blue line is the mains signal and the yellow line is the "Power Good" signal. The latter is de-asserted to a low state when any of the +12V, 5V, or 3.3V output voltages fall below the undervoltage threshold, or after the mains power has been removed for a sufficiently long time to guarantee that the PSU cannot operate anymore.



The hold-up time our scope measured was too low. We know that APFC caps are expensive, but such doesn't justify the ERX430AWT's lousy performance in this test. Enermax should know and do better.

Inrush Current

Inrush current or switch-on surge refers to the maximum, instantaneous input-current drawn by an electrical device when it is first turned on. Because of the charging current of the APFC capacitor(s), PSUs produce large inrush-current right as they are turned on. Large inrush current can cause the tripping of circuit breakers and fuses and may also damage switches, relays, and bridge rectifiers; as a result, the lower the inrush current of a PSU right as it is turned on, the better.



Registered inrush current was very low, the only positive of the unit's very small bulk cap.

Load Regulation and Efficiency Measurements

The first set of tests revealed the stability of the voltage rails and the ERX430AWT's efficiency. The applied load was equal to (approximately) 10%-110% of the maximum load the PSU can handle, in 10% steps.

We conducted two additional tests. In the first test, we stressed the two minor rails (5V and 3.3V) with a high load while the load at +12V was only 0.10 A. This test reveals whether the PSU is Haswell ready or not. In the second test, we dialed the maximum load the +12V rail could handle while the load on the minor rails was minimal.

Load regulation on the +12V rail was good enough; however, it wasn't as tight on the other rails, though both minor rails managed to stay within 3%. 3% was pretty tight several years ago, but even affordable PSUs do better nowadays. The ERX430AWT did well enough in terms of efficiency, but we would like to see better results in the 20% and full-load tests. Its maximum efficiency was close to 91.5% and took place in the 50% of its max-rated-capacity load test—decent performance for a Gold-certified unit utilizing an older platform. More expensive high-end units with the same certification achieve close to 93% efficiency with the same load range.

In the above tests, the unit's fan spun at slow speeds at up to 40% load, but it increased its speed noticeably afterward and was quite loud with 80% and more load. Please note that the unit shut down during the full-load and overload tests once ambient temperatures reached 44°C. The unit, to be exact, failed to deliver its full load after only 3-4 minutes at above 44°C and shut down after only 1 minute in the overload test. OTP (Over Temperature Protection) obviously kicked in to save the PSU. Such triggers are important and it is good to see OTP work properly, but we would also like the unit to deliver its full load successfully at 45°C over prolonged periods of time.