The PSL-6850P was placed under a load of 886 watts. This counts for a total of 104% of the power supplies rated output. At this load, the power supply required 1042 watts from the mains. Therefore the efficiency of this power supply can be found by a simple equation: (886 / 1042) * 100, which works out to be an efficiency rating of 85.0%.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
After finding out that the PSL-6850P was cooled by two 44dba+ fans, I must admit thinking that this was going to be one very loud PSU indeed. However, it would seem that Zippy have done a good job of controlling the fan speeds at idle and under medium load with the unit sounding significantly quieter than I was expecting.
At full load, the fan speed slowly increased to counteract the extra heat being produced by the unit. This in turn increased the noise output of the unit significantly making it rather loud - as you will be able to hear from the recordings above.