Seasonic X-Series KM3 650 W Power Supply Review
Ripple and Noise Tests
Contents
Volta
ges 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 KM3 650 W provided extremely low ripple and noise levels, as you can see in the table below.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 15.0 mV | 21.2 mV | 25.0 mV | 28.8 mV | 33.2 mV |
| +12VB | 15.8 mV | 23.0 mV | 27.2 mV | 32.2 mV | 38.4 mV |
| +5 V | 10.0 mV | 10.4 mV | 10.8 mV | 11.6 mV | 12.8 mV |
| +3.3 V | 7.8 mV | 8.6 mV | 9.8 mV | 11.2 mV | 12.0 mV |
| +5VSB | 5.0 mV | 6.0 mV | 7.0 mV | 7.2 mV | 7.4 mV |
| -12 V | 14.0 mV | 18.4 mV | 22.4 mV | 24.0 mV | 31.8 mV |
Below you can see the waveforms of the outputs during test five.
Figure 25: +12VA input from load tester during test five at 649.8 W (33.2 mV)
Figure 26: +12VB input from load tester during test five at 649.8 W (38.4 mV)
Figure 27: +5V rail during test five at 649.8 W (12.8 mV)
Figure 28: +3.3 V rail during test five at 649.8 W (12.0 mV)
Let’s see if we can pull more than 650 W from this unit.