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 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 L8-730W 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 L8-730W. 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.


Efficiency is very good for a plain Bronze unit and at 40% of max rated capacity it peaks at nearly 88%. On the other hand voltage regulation isn't so great since +12V exceeded 3% deviation and 3.3V rail is very close to the 5% limit. Only 5V managed to stay within 3%. During the execution of the above tests we discovered that Over Temperature Protection kicks in at about 43-45°C operating temperature. In order to run the full load test we had to leave the hot box open for a while to lower its internal temperature, because with over 43°C ambient the PSU kept shut down after a while. Although the OTP trigger point is a little low (for our taste at least) since the PSU is not 50°C rated, we would like to note here that we found very this protection useful since it gave us the chance to find the actual thermal limits of the unit without worrying about a possible failure due to overheating. Normally all PSUs that can't handle high operating temperatures should be equipped with OTP, in order to avoid fatal damages.

Efficiency at Low Loads

In the next tests, we measure the efficiency of L8-730W 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, 80 and 100W (for PSUs with over 500W capacity). This is important for scenarios in which a typical office PC is in idle with power saving turned on.


Efficiency at low loads is fairly good for the efficiency rating of the unit. With 60W we measured close to 80% efficiency and with 80W and 100W the aforementioned mark was easily surpassed.

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 is way higher than the respective limits. At the last two tests is also higher than the 70% mark but still significantly below 80%.

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).


The PSU consumes very little power in standby mode and passes the ErP Lot 6 requirements with flying colors.