Be Quiet! Straight Power E9 680W Review
Ryan Martin / 11 years ago
Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs.
The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications.
| Load (%) | 3.3V Ripple | 5V Ripple | 12V Ripple |
| 20 |  |
 |
 |
| 40 |  |
 |
 |
| 60 |  |
 |
 |
| 80 |  |
 |
 |
| 100 |  |
 |
 |
The Be Quiet Straight Power E9 680W power supply had good ripple and noise suppression on all rails. The 5 volt rail was the strongest with less than 18mv while the 3.3 volt rail fared slightly worse with less than 25 mv – but that is still really good and well within ATX specification. The 12 volt rail had less than 25mv which again is very solid and well within ATX specifications.
