Chieftec SFX 500GD-C 500w Power Supply Review

by - 5 years ago

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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

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  7  7.8  12.8
40  8  10.4  19.8
60  9.6  13.2  27.4
80  10.4  16.2  40.4
100  16.6  22.6  55.6

Ripple was pretty good across the board. Sure, it’s a little high at 12v at 100% load, but it’s still within a safe margin and about where I expected it to be for a compact unit such as this.

3.3 volt @ 100%

3.3

5 volt @ 100%

5

12 volt @ 100%

12

Article Index

  1. Introduction and Packaging
  2. A Closer Look - Exterior
  3. A Closer Look - Interior
  4. Test Procedure
  5. Efficiency, PFC and Voltage Regulation
  6. Ripple Testing
  7. OPP and Max Wattage
  8. Fan Speed
  9. Final Thoughts
  10. View All

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