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Ripple Measurements
To learn how we measure ripple, please click here.
The following table includes the ripple levels we measured on the SDA600's rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V and 5VSB).
| Test | 12V | 5V | 3.3V | 5VSB | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 17.4mV | 21.4mV | 26.6mV | 10.6mV | Pass |
| 20% Load | 19.3mV | 20.5mV | 29.5mV | 11.4mV | Pass |
| 30% Load | 25.1mV | 22.7mV | 34.1mV | 11.5mV | Pass |
| 40% Load | 21.2mV | 23.3mV | 38.9mV | 11.4mV | Pass |
| 50% Load | 22.6mV | 25.6mV | 43.7mV | 11.8mV | Pass |
| 60% Load | 22.0mV | 27.5mV | 49.6mV | 16.1mV | Pass |
| 70% Load | 23.0mV | 29.2mV | 54.9mV | 19.7mV | Fail |
| 80% Load | 23.2mV | 30.0mV | 62.5mV | 17.3mV | Fail |
| 90% Load | 27.1mV | 33.2mV | 63.7mV | 18.1mV | Fail |
| 100% Load | 27.5mV | 35.1mV | 68.2mV | 20.7mV | Fail |
| 110% Load | 27.9mV | 36.6mV | 72.6mV | 21.6mV | Fail |
| Cross-Load 1 | 18.6mV | 21.0mV | 33.0mV | 6.1mV | Pass |
| Cross-Load 2 | 26.2mV | 24.5mV | 72.6mV | 17.5mV | Fail |
It looks like FSP paid great attention to ripple suppression at +12V (the most important rail), but totally ignored the 3.3V rail. From the 70% load test and beyond, it goes out of control.
We're disappointed to see a high-end SFX unit unable to keep its ripple within the ATX spec's limits, which are already set very high. We had a couple of SDA600s in our possession, so we tested both of them to check for a possible bad sample. Unfortunately, the second unit's performance was identical. That means the 3.3V module has a problem FSP needs to fix.
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 0.01 V/Div (each vertical division/box equals 0.01V) as the standard for all measurements.
Ripple At Full Load
Ripple At 110-Percent Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
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