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. The AC source is a Chroma 6530 capable of delivering up to 3 kW of power. 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), a Keithley 2015 THD 6.5 digit bench DMM, 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 we 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 more accurately, 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.

We use a GPIB-USB controller to control the Chroma 6530 source, which allows us to avoid its incredibly picky serial port. This controller was kindly sponsored by Prologix.

Primary Rails Load Regulation

The following charts show the voltage values of the main rails, recorded over a range of 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 didn't reach or exceed 16 ms, so the unit failed this test.

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.



The PSU's inrush current was very low for its huge capacity. The large NTC thermistor and the relay that allow it to cool down fast did a fine job here.

Load Regulation and Efficiency Measurements

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

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

Load regulation was very good for a PSU with a capacity of 2 kW. The +12V rail stayed close to 1.2% and the other rails didn't exceed 2.5%. The unit also easily cleared Platinum 230V EU efficiency requirements with 20% and 100% load despite the high ambient at which we conducted those tests, and it only fell short at 50% of its maximum-rated capacity. However, we evaluated the unit at an ambient that was almost 20°C higher than in Ecova's tests, so the Leadex unit will easily crack 94% efficiency with 50% load with normal ambient temperatures. It really is amazing to see such a strong PSU without digital circuits deliver such incredible efficiency in a worst-case scenario. As there is currently no alternative with 2 kW, Super Flower created an impressive platform that can easily meet the lower-wattage competition eye-to-eye in terms of efficiency.

The temperature inside the hot box reached 47.5°C with almost 2200 W, but the Leadex unit didn't run into even the slightest problem during our prolonged testing sessions. At some point, the thermal protection of the power strip to our Chroma 6530 AC source triggered, so we had to replace it with one without thermal protection to complete our full load and overload tests. This was a first even for us, but we are prepared for anything, especially when it comes to pushing such a PSU's limits.

The output-noise column nicely shows that the Leadex unit is noisy as hell, especially once its fan ramps up, which is as expected since there is no easy way to provide 2 kW and a silent operation. Such would only be possible with liquid-cooling, but including such a setup would influence usability and price.