Seasonic X-Series 750 W Power Supply Review
Ripple and Noise Tests
Contents
Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.
The Seasonic X-Series 750 W provided extremely low ripple and noise levels, making it a “flawless” unit here as well.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 9.2 mV | 14.0 mV | 11.2 mV | 9.8 mV | 12.6 mV |
| +12VB | 9.8 mV | 14.4 mV | 13.2 mV | 13.0 mV | 16.2 mV |
| +5 V | 10.4 mV | 11.2 mV | 12.2 mV | 12.8 mV | 15.2 mV |
| +3.3 V | 10.8 mV | 11.2 mV | 12.8 mV | 15.4 mV | 15.4 mV |
| +5VSB | 11.4 mV | 16.2 mV | 15.6 mV | 18.6 mV | 20.6 mV |
| -12 V | 25.2 mV | 30.2 mV | 32.4 mV | 44.8 mV | 54.6 mV |
Below you can see the waveforms of the outputs during test five.
Figure 19: +12VA input from load tester during test five at 748.2 W (20.2 mV)
Figure 20: +12VB input from load tester during test five at 748.2 W (18.6 mV)
Figure 21: +5V rail during test five at 748.2 W (9.2 mV)
Figure 22: +3.3 V rail during test five at 748.2 W (12.2 mV)