At idle the HX620 was placed under a total load of 203 watts with a recording of 253 watts consumption being obtained from the mains. Therefore the efficiency of the HX620 at idle worked out to be 80.2%.
Increasing the load on the unit produced even more favourable results, with the HX620 managing 83.8% efficiency when being placed under a total load of 646 watts.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
At idle the HX620 was extremely quiet with the 120mm fan running at a very low RPM. As the load on the unit was increased, the fan gradually gained speed in order to counteract the extra heat produced by the PSU's components. Even at full load the HX620 managed to keep a good balance between the noise and heat output of the unit, proving that Seasonic's implimentation of a 60mm fan on their M12 PSU was not necessarily required.