The M12 was placed under a load of 646 watts. This counts for a total of 107% of the power supplies rated output. At this load, the power supply required 771 watts from the mains. Therefore the efficiency of this power supply can be found by a simple equation: (646 / 771) * 100, which works out to be an efficiency rating of 83.7%.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
After hearing good things about the Seasonic units with regards to noise levels, I was expecting the M12 to be a very quiet power supply. However, these expectations started to turn into concerns once I had seen the choice of fans used inside the unit. With two fans rated between 32dBA and 39dBA it became hard to see how these could possibly be considered "Super quiet" as stated on the M12's packaging.
At Idle I started to regain faith in Seasonic's "super quiet" marketing, with the M12 being almost totally silent due to both fans running at very low RPM.
However, once the M12 was placed under load the fan speed increased significantly, and as you can probably hear from the recordings above - made the unit really quite loud. Personally I would find it very hard to recommend the M12 to anybody seeking a silent PSU for their computer.