The EvoStream 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 831 watts from the mains. Therefore the efficiency of this power supply can be found by a simple equation: (646 / 831) * 100, which works out to be an efficiency rating of 77.7%.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
As you can probably hear from the recordings above, the EvoStream is not a silent power supply. At idle the fan is clearly audible both inside and outside of a PC case, and left me wondering if the fan really did need to run so fast as very little heat was pushed out of the unit. At load the fan speed increased significantly making the unit louder still. Personally I would not recommend this power supply for anybody seeking a silent PC setup.