Ripple Measurements
You will see the ripple levels that we measured on the main rails of the ST50F-ES in the following table. The limits are, according to the ATX specification, 120 mV (+12V) and 50 mV (5V, 3.3V, and 5VSB).
Ripple Measurements Silverstone ST50F-ES |
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Test | 12 V | 5 V | 3.3 V | 5VSB | Pass/Fail |
20% Load | 13.0 mV | 12.1 mV | 13.2 mV | 12.5 mV | Pass |
40% Load | 18.6 mV | 18.3 mV | 21.9 mV | 19.3 mV | Pass |
50% Load | 20.7 mV | 21.0 mV | 25.1 mV | 23.5 mV | Pass |
60% Load | 22.5 mV | 22.7 mV | 27.7 mV | 28.1 mV | Pass |
80% Load | 35.2 mV | 27.6 mV | 35.6 mV | 35.5 mV | Pass |
100% Load | 45.8 mV | 30.1 mV | 40.4 mV | 43.1 mV | Pass |
110% Load | 52.0 mV | 33.5 mV | 43.5 mV | 47.8 mV | Pass |
Crossload 1 | 18.2 mV | 32.8 mV | 27.2 mV | 11.7 mV | Pass |
Crossload 2 | 38.5 mV | 33.8 mV | 39.7 mV | 42.5 mV | Pass |
Ripple suppression at +12V is very good for a budget unit, not a high-end unit, and is good enough at 5V. Ripple at higher loads is on the high side on the 3.3V and 5VSB rails, and we think that a little better performance here would significantly help this PSU achieve a much higher performance rating. Nevertheless, since all minor rails register noticeably lower ripple than the maximum allowed, we don't have much to complain about, especially at such a price.
Ripple at Full Load
You can see the AC ripple and noise that the main rails registered (+12V, 5V, 3.3V, and 5VSB) in the following oscilloscope screenshots. The bigger the fluctuations on the oscilloscope's screen, the bigger the ripple/noise. For all measurements, we set 0.01 V/Div (each vertical division/box equals 0.01 V) as standard.
Ripple at 110% Load
Ripple at Crossload 1
Ripple at Crossload 2