be quiet! System Power U9 700W PSU Review

1. Introduction2. Packaging, Contents & Exterior3. Teardown & Component Analysis4. Load Regulation, Hold-Up Time & Inrush Current5. Efficiency, Temperature & Noise6. Protection Features & DC Power Sequencing7. Cross-Load Tests & Infrared Images8. Transient Response Tests9. Ripple Measurements10. EMC Pre-Compliance Testing11. Performance, Value, Noise & Efficiency12. Final Analysis13. View All Pages

To learn how we measure ripple, please click here.

The following table includes the ripple levels we measured on the SU9-700’’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	9.6 mV	6.1 mV	5.8 mV	5.2 mV	Pass
20% Load	13.4 mV	7.1 mV	7.1 mV	6.7 mV	Pass
30% Load	15.3 mV	7.6 mV	7.6 mV	6.1 mV	Pass
40% Load	20.5 mV	8.3 mV	8.5 mV	7.3 mV	Pass
50% Load	25.2 mV	29.1 mV	15.5 mV	9.7 mV	Pass
60% Load	30.6 mV	11.7 mV	11.4 mV	11.4 mV	Pass
70% Load	37.3 mV	12.3 mV	12.7 mV	10.0 mV	Pass
80% Load	43.3 mV	12.8 mV	15.5 mV	10.8 mV	Pass
90% Load	47.3 mV	31.6 mV	24.2 mV	11.8 mV	Pass
100% Load	55.2 mV	22.8 mV	24.9 mV	11.0 mV	Pass
110% Load	65.4 mV	30.0 mV	34.1 mV	13.3 mV	Pass
Crossload 1	11.4 mV	11.8 mV	16.6 mV	5.7 mV	Pass
Crossload 2	53.0 mV	12.5 mV	11.0 mV	9.2 mV	Pass

The ripple suppression is not that good at +12V. We would like to see below 50mV on this rail and ideally less than 40mV. On the minor rails the performance is better.

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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