When switching power supply is the most efficient
According to design parameters set.
Under normal circumstances, full load time is higher than the no-load.
This is the design of the time according to the different needs of customers set
Generally should be in the 80% load, rated input, a certain temperature under the circumstances to obtain the highest efficiency
Specific reference to the power supply specifications
This is basically not the same, the ideal design is full load output rated voltage input for the highest efficiency