Ripple Measurements
You will see the ripple levels that we measured on the main rails of the ST65F-G 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 ST65F-G |
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Test | 12 V | 5 V | 3.3 V | 5VSB | Pass/Fail |
20% Load | 65.7 mV | 26.9 mV | 15.4 mV | 13.9 mV | Pass |
40% Load | 50.8 mV | 28.9 mV | 15.5 mV | 19.7 mV | Pass |
50% Load | 54.1 mV | 29.7 mV | 17.2 mV | 19.9 mV | Pass |
60% Load | 55.4 mV | 33.8 mV | 19.0 mV | 23.8 mV | Pass |
80% Load | 61.1 mV | 39.6 mV | 22.3 mV | 33.1 mV | Pass |
100% Load | 70.9 mV | 43.0 mV | 26.3 mV | 44.7 mV | Pass |
110% Load | 79.2 mV | 46.1 mV | 29.6 mV | 52.8 mV | Fail |
Crossload 1 | 90.9 mV | 43.1 mV | 20.0 mV | 31.7 mV | Pass |
Crossload 2 | 71.7 mV | 36.3 mV | 25.8 mV | 45.2 mV | Pass |
Ripple suppression definitely isn't one of the strong points of this unit. The maximum reading at +12V exceeded 70 mV, and although the limit is much higher, we are not used to seeing over 50-60 mV on PSUs of this price range. Ripple suppression was even worse at 5V, since the worst reading was much closer to the corresponding limit, but readings on the 3.3V rail were definitely much better. The mediocre performance of the unit in this area was topped off by its bad 5VSB performance with a fail during the 110% load test, but we won't deduct any performance points for this failure because this test forces the PSU to operate outside of its normal specifications. Enhance and Silverstone should, together, take a look at the ripple suppression performance of the ST65F-G to make the necessary changes for an improvement; that is, if they want to catch up with the tough competition. We expect much better results in crucial areas like ripple suppression from a PSU of this price category.
Ripple at Full Load
In the following oscilloscope screenshots, you can see the AC ripple and noise that the main rails registered (+12V, 5V, 3.3V, and 5VSB). 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