We did expect the efficiency of the Be Quiet! Dark Power Pro 10 650W power supply to be very high since it comes with an 80Plus Gold certification, yet it still managed to positively surprise us by delivering figures which would easily earn it a Platinum certification if the test were to be conducted only with a 110V A/C source. Unfortunately, with Be Quiet! being a European company, the power supply could not reach the efficiency required at 50% to earn it an 80Plus Platinum certification when a 230V A/C source is being used. Still, the efficiency is generally significantly higher than most other 80Plus Gold certified power supplies.
The Be Quiet! power supply does live up to its name, with the volume levels remaining below 26.5dB(A) even under maximum load, making this power supply whisper-quiet under normal operating conditions. For reference, 25-26dB(A) is the point where the humming noise from the PSU becomes discernible over a distance of 1m.
It is common for units which display low noise levels to have mediocre thermal performance but this is not the case with the Dark Power Pro 10 650W unit. Apparently, the high electrical efficiency and the good Silent Wings cooling fan do create a great cooling combination, as the running temperatures remain very low despite the low rotational speed of the fan.