Test Setup

All measurements are performed utilizing ten electronic loads (seven Array 3711A, 300W each, and three Array 3710A, 150W each), which are able to deliver over 2500W of load and are controlled by a custom made software. We also use a Picoscope 3424 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 four more oscilloscopes (Rigol 1052E and VS5042, Stingray DS1M12 and a second Picoscope 3424) 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. Finally, if the manufacturer states that the maximum operating temperature of the test unit is only 40°C then we try to stay near this temperature, otherwise we crank up the heat inside the hotbox up to 45-50°C.

Voltage Regulation Charts

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

5VSB Regulation Chart

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

Efficiency Chart

In this chart you will find the efficiency of AU-500FL 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 AU-500FL. 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 minimal.


Since the PSU doesn't have a fan it is natural that the temperature on its top exhaust grill is much higher than the one measured on the front grill (remember that hot air is lighter than the cool air, so it rises). Also as you can see we stayed near 40°C ambient since FSP doesn't provide any info on the unit's max. operating temperature and the lack of OTP could lead to a big "bang" if we over-stressed the PSU, so we opted to stay on the safe side.
The small Aurum registered high efficiency and tight voltage regulation overall, especially on the +12V rail which is the one that matters the most. It is very nice to see modern, high efficiency, units being able to keep tight voltage regulation. This in the recent past was very difficult to accomplish, since in their efforts to increase efficiency, the manufacturers tight voltage regulation.

Efficiency at Low Loads

In the next tests, we measure the efficiency of AU-500FL 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, 60 and 80W. This is important for scenarios in which a typical office PC is in idle with power saving turned on.


As we expected, due to its low capacity the AU-500FL registers high efficiency even at very low load levels. Indeed even with mere 40W load, efficiency reaches 78% and with 60W and 80W it is far above 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 the 5VSB rail is highly efficient while in the last two, although it easily surpasses the 70% mark that the ATX spec specifies, efficiency surely is not among the highest we have ever seen. Nevertheless a near 75% reading cannot be classified as low when we are referring to 5VSB.

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).


Phantom power is really low in this fellow and it barely exceeds 0.1W. As it seems ErP Lot 6 compliance is an easy task for most modern units and this is very good for the environment (and your wallet, too).