The Etasis was placed under a load of 646 watts. This counts for a total of 86% of the power supplies rated output. At this load, the power supply required 790 watts from the mains to produce the 646 watts required by our custom made power supply tester. Therefore the efficiency of this power supply can be found by a simple equation: (646 / 790) * 100 that works out to be an efficiency rating of 81.7%.


Noise Testing

Possibly the hardest part of any PSU review is summarising the level of noise given out by the unit. The threshold for what is considered 'noisy' varies from person to person and therefore what I may consider a quiet unit, another person may consider extremely loud. A common way to resolve this issue is to use a dBA meter to measure the units noise level, however this doesn't take into account the pitch (type) of noise emitted and whether it is likely to irritate end users.

For this reason OC3D records all power supplies at idle and load in wav format for you to make your own informed decisions. All recordings are taken at 30cm away from the PSU and outside of a PC case. You will need to remember that noise levels will be reduced by varying amounts once the PSU has been installed inside your PC enclosure.

Idle Recording - Download
Load Recording - Download

Under idle conditions the fan speed was significantly throttled. This meant that all that could be heard was the whisper of air moving around the unit.
When placed under load, the ET750 gradually increased the fan speed to counteract the heat. As you can hear from the recording above, the ET750 was fairly noisy. With the Etasis installed inside a PC case this should be much more reasonable.