SilverStone ST45SF-G 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 reason why we tested two samples of the SilverStone ST45SF-G was because the first sample we received provided ripple and noise levels above the maximum allowed at the +3.3 V output. Wondering if we received a defective product, we asked the manufacturer for a second sample, which passed our tests, as you can see below.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 26.8 mV | 27.2 mV | 36.6 mV | 41.4 mV | 53.2 mV |
| +12VB | 25.8 mV | 26.2 mV | 34.4 mV | 39.2 mV | 51.4 mV |
| +5 V | 14.8 mV | 18.2 mV | 22.8 mV | 28.2 mV | 34.4 mV |
| +3.3 V | 10.6 mV | 12.8 mV | 15.4 mV | 20.6 mV | 25.4 mV |
| +5VSB | 9.8 mV | 12.2 mV | 14.0 mV | 20.2 mV | 22.6 mV |
| -12 V | 29.0 mV | 38.2 mV | 53.4 mV | 89.2 mV | 99.8 mV |
Below you can see the waveforms of the outputs during test five.
Figure 22: +12VA input from load tester during test five at 449.8 W (53.2 mV)
Figure 23: +12VB input from load tester during test five at 449.8 W (51.4 mV)
Figure 24: +5V rail during test five at 449.8 W (34.4 mV)
Figure 25: +3.3 V rail during test five at 449.8 W (25.4 mV)
Let’s see if we can pull more than 450 W from this unit.