XFX PRO 1250W Black Edition Modular Power Supply Review
Ryan Martin / 10 years ago
Ripple
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. millivolt ripple is measured by the peak to peak size of the voltage curve.
![sample_scalev2](http://www.eteknix.com/wp-content/uploads/2014/07/sample_scalev2.jpg)
Sample Ripple Graph
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. Millivolt figures are stated to the closest increment of 5 given their variability.
Load (%) | 3.3V Ripple | 5V Ripple | 12V Ripple |
20 | 15 | 15 | 20 |
40 | 15 | 15 | 20 |
60 | 15 | 15 | 25 |
80 | 20 | 20 | 30 |
100 | 20 | 25 | 35 |