To learn how we measure ripple, please click here.
The following table includes the ripple levels we measured on the Edison M 750's rails. The limits are, according to the ATX specifications, 120mV (+12V) and 50mV (5V, 3.3V and 5VSB).
|Test||12V (mV)||5V (mV)||3.3V (mV)||5VSB (mV)||Pass/Fail|
Ripple suppression on all rails (except for 5V) is very good overall. On the 5V rail, we noticed a sudden increase in ripple with 80-percent load and up. Incidentally, this was also the case with the Edison M 650W that we tested previously. We would advise Seasonic to look at the DC-DC converter that generates the 5V rail to find the source of this sudden increase at higher loads. It might not be a serious problem that could affect your system’s stability, since ripple on this rail is still lower than the ATX limit. But it's still a shame to see performance loss over this matter.
Ripple Oscilloscope Screenshots
The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the screen, the bigger the ripple/noise. We set 0.01V/Div (each vertical division/box equals 0.01V) as the standard for all measurements.