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 the SF-650P14PE 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 the SF-650P14PE. 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.


This PSU exhibits high efficiency overall, although with 20% load we would like to see an over 91% reading. Voltage regulation at +12V is very tight and currently the best in its category, among all units we have tested so far. The 5V rail managed to stay marginally below 3% deviation while the 3.3V rail is near 3.5%. Not bad but definitely not the tightest voltage regulation we have ever seen from these two rails. From the temperature column of the table above you will notice that input temperature until 50% load is higher than output. This is happening because the unit operated in fanless mode, so the hot air went upwards toward the input temperature probe. Once the fan started to spin things went back to normal again and output temperature was much higher than the input one. Speaking about temperature this unit at full load and CL2 tests easily proved that it has no problem working at over 50°C, delivering its full power for long periods of time. This shows that its components are of high quality and can easily cope with the unit's max power. Finally even when the fan was engaged and probably at its full RPMs, it was fairly quiet.

Efficiency at Low Loads

In the next tests, we measure the efficiency of the SF-650P14PE 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 very high, especially at 60W and beyond. Only at test#1 the PSU didn't manage to surpass the 80% mark but it was really close to it. With the new power saving techniques that effectively lower CPU and GPU frequencies at idle, energy consumption is dramatically decreased so a PSU with good efficiency at such low loads will be highly beneficiary for the environment and your wallet.

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.


The 5VSB rail isn't among the strong points of this PSU, at least as far as efficiency is concerned. At test#1 it failed to pass the corresponding mark while at all other tests it did so but not by a large margin. Judging from the efficiency of all other rails we would like to see a more efficient 5VSB converter in this PSU. Don't get me wrong, 5VSB is not bad, but the other results in this review set very high standards, and 5VSB is just not as impressive as the rest.

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 restricted below 0.5W, so this PSU not only meets the current ErP Lot 6 directive but also the future one which will be effective from the beginning of 2013.