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Ripple Measurements
The following table includes the ripple levels we measured on CS850M’s rails. The limits are, according to the ATX specification, 120mV (+12V) and 50mV (5V, 3.3V and 5VSB).
| Test | 12V (mV) | 5V (mV) | 3.3V (mV) | 5VSB (mV) | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 20.4 | 4.8 | 12.3 | 10.1 | Pass |
| 20% Load | 18.4 | 5.3 | 11.6 | 13.3 | Pass |
| 30% Load | 18.5 | 6.1 | 11.6 | 13.7 | Pass |
| 40% Load | 20.9 | 6.8 | 11.8 | 14.3 | Pass |
| 50% Load | 24.5 | 7.5 | 12.7 | 14.3 | Pass |
| 60% Load | 30.4 | 8.8 | 14.0 | 16.8 | Pass |
| 70% Load | 33.5 | 9.5 | 14.2 | 18.6 | Pass |
| 80% Load | 38.7 | 10.5 | 15.0 | 19.5 | Pass |
| 90% Load | 43.9 | 11.9 | 14.4 | 19.3 | Pass |
| 100% Load | 49.4 | 13.1 | 12.6 | 23.3 | Pass |
| 110% Load | 54.3 | 14.3 | 12.1 | 24.4 | Pass |
| Cross-Load 1 | 25.1 | 6.5 | 12.3 | 8.4 | Pass |
| Cross-Load 2 | 49.7 | 12.6 | 11.6 | 15.1 | Pass |
Ripple suppression on the minor rails is excellent, matching the performance of higher-end platforms built using much better components. However, while the initial performance of Taiwanese and Chinese capacitors may be good, what matters most is how they perform after a prolonged period. The caps in this unit are going to age much faster than Japanese caps.
Ripple suppression is decent on the +12V rail; we would prefer to see readings below 40mV during the full-load tests. Still, even some high-end PSUs register close to 40mV on this rail under worst-case conditions, so the CS850M's +12V ripple suppression can’t be characterized as bad or even mediocre.
Ripple
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.
Ripple At Full Load
Ripple At 110-Percent Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
