Test Setup

All measurements are performed utilizing nine electronic loads (six Array 3711A, 300W each, and three Array 3710A, 150W each), which are able to deliver over 2000W of load and are controlled by a custom made software. We also use a DS1M12 (Stingray) oscilloscope, a CHY 502 thermometer, a Fluke 175 multimeter and an Instek GPM-8212 power meter. Furthermore, in our setup we have included a wooden box, which along with a heating element is used as a Hot Box. Finally, we have at our disposal two more oscilloscopes (Rigol 1052E and VS5042) and a CEM DT-8852 sound level meter. In this article you will find more details about our equipment and the review methodology we follow.

Voltage Regulation Charts

The following charts show the voltage values of the main rails, recorded over a range from 70W to the maximum specified load, and the deviation (in percent) for the same load range.

Efficiency Chart

In this chart you will find the efficiency of HCG-520 at low loads and at loads equal to 20-100% of PSU’s maximum rated load.

Voltage Regulation and Efficiency Measurements

The first set of tests reveals the stability of voltage rails and the efficiency of HCG-520. The applied load equals to (approximately) 20%, 40%, 50%, 60%, 80% and 100%, of the maximum load that the PSU can handle. In addition, we conduct two more tests. In the first we stress the two minor rails (5V & 3.3V) with a high load, while the load at +12V is only 2A and in the second test we dial the maximum load that +12V can handle while load at minor rails is minimum.


Voltage regulation at +12V is pretty tight, reaching an amazing 1.1%, a very small deviation for the price tag and the category of HCG-520. On the other hand the minor rails registered loose voltage regulation but still within 5%, the ATX limit. Efficiency is nothing to write home about and with full load it drops under 84%. However from an 80 Plus Bronze PSU we couldn't ask for more. Finally, at CL1 test the weakness of group regulated designs in unbalanced loads is clearly shown. Thankfully the loads we applied at CL1 test are not a realistic real life scenario since no contemporary system stresses the minor rails so much.

Efficiency at Low Loads

In the next tests, we measure the efficiency of HCG-520 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dial are 40, 70 and 100W. This is important for scenarios in which a typical office PC is in idle with power saving turned on.


Efficiency at low loads is good for a Bronze 520W PSU. Only with 40W load it's lower than the 80% mark.

5VSB Efficiency

ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100mA load, 60% or higher with 250mA load and 70% or higher with 1A or more load.
We will take four measurements, three at 100 / 250 / 1000 mA and one with the full load that 5VSB rail can handle.


In the first two tests efficiency at 5VSB is worse than the ATX spec recommendation, not by a large degree though, while in the other two remaining tests it is higher than the 70% mark. With full load at 5VSB we measured a very good 82.71% ratio.

Power Consumption in Idle & Standby

In the table below you will find the power consumption and the voltage values of all rails (except -12V), when the PSU is in idle mode (On but without any load at its rails) and the power consumption when the PSU is in standby (without any load at 5VSB).


With 0.31W phantom power the HCG-520 passes the ErP Lot 6 2010 requirements with flying colors and is ready for the future 2013 ones.