The S75EPS 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 779 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 / 779) * 100 that works out to be an efficiency rating of 82.9%.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
½ Load Recording - Download
Load Recording - Download
At idle I found the unit to be almost inaudible, even with my ear up close to the exhaust fan.
Increasing the load on the PSU to half of its rated output caused the fan controller to bump up the fan speed. However, at this speed the unit remained at a perfectly acceptable noise level which even a HTPC user would find hard to fault.
At full load the Silencer increased the fan speed by a significant amount, causing the noise levels to increase at the same time. Personally i would say that the noise output was on the verge of acceptable for my tollerances. It is worth remembering that the average user will find it hard to place the Silencer under this amount of stress, but in my opinion PCP&C could have chosen a better fan to cool the unit.