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 SP-730P 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 SP-730P. 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.


Voltage regulation is loose on all rails. Especially the 3.3V rail registered a deviation which by far exceeded 5%, reaching 6.23%. Also the results at Crossload tests were really bad and the main cause for this is the group regulation design used in the secondary side of the PSU. Efficiency isn't bad at all since it easily met the 80 Plus requirements and it peaked at 87.18% with 40% load. As you can see from the table above, at full load and CL2 tests we had to lower the ambient inside the hot box to complete the measurements, because with anything above 40°C the PSU kept shutting down. Apparently the manufacturer was not lying about the max operating temperature which is restricted at 40°C.

Efficiency at Low Loads

In the next tests, we measure the efficiency of SP-730P 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.


At low loads efficiency is pretty good, especially if we take into account the low official efficiency rating of the unit. In two out of the four tests we got over 80% readings, a clear indication that this unit will save you money from electricity bills if your system idles around 80-100W.

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.


5VSB efficiency in all tests is constantly above the corresponding limits, however with full load it registers a minor efficiency drop compared to test#3 and as you can also see the voltage reading registers a significant drop. This means that 3A is the limit for 5VSB, if not a little above it.

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).


Vampire power is very low, making this unit compatible not only with the ErP Lot 6 2010 directive but with the future 2013 version, too.