Test Setup

All measurements are performed utilizing a custom designed and built load tester, called Faganas, which is able to stress PSUs up to 1800 Watts. 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 nine electronic loads (six Array 3711A, 300W each, and three Array 3710A, 150W each), a Rigol 1052E oscilloscope and a CEM DT-8852 sound level meter. In the near future the electronic loads will form our new test set up, which with the help of our custom built software will have the same capabilities with the, ultra expensive, Chroma ATEs. 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 60W to the maximum specified load, and the deviation (in percent), when compared with the voltage values at 60W load.

Efficiency Chart

In this chart you will find the efficiency of SP-E8 400W 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-E8 400W. 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 the maximum load that our tester can apply to these rails, 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.


Efficiency is really high for a plain 80 Plus Bronze unit. It peaks at an impressive 89.07% with 40% of max rated capacity load. Even at full load it is 87%. Voltage regulation at +12V is quite good registering 1.64% deviation, at 5V a little over 3% and at 3.3V almost at the 5% limit. We wanted to see much tighter voltage regulation at 3.3V. Finally although Be Quiet! states that the max operation temperature is 40°C the PSU didn't have a problem to work at nearly 50°C. Finally throughout all tests the fan rotated with low RPMs, making equally low noise, so the temperature delta between In/Out temperatures was small.

Efficiency at Low Loads

In the next tests, we measure the efficiency of SP-E8 400W 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 (approximately) 40, 65 and 90W. This is important for scenarios in which a typical office PC is in idle with power saving turned on.


Efficiency is pretty high at low loads too. With only 42W it is almost 80%, a very good level for such a low load. With 25W more power draw, efficiency leaps to 84.6%.

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 only 0.18W so the unit is ErP Lot 6 ready. Actually not only meets the 2010 requirements but the 2013 ones too, where standby power consumption limit is halved (<0.5W).