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be quiet! System Power U9 700W PSU Review


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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