Ripple Measurements
To learn how we measure ripple, please click here.
This table includes the ripple levels we measured on the TX750M's rails. The limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).
| Test | 12V | 5V | 3.3V | 5VSB | Pass/Fail |
|---|---|---|---|---|---|
| 10% Load | 16.5mV | 5.3mV | 7.9mV | 4.3mV | Pass |
| 20% Load | 23.2mV | 6.3mV | 8.7mV | 6.0mV | Pass |
| 30% Load | 21.3mV | 9.0mV | 17.2mV | 7.2mV | Pass |
| 40% Load | 22.2mV | 7.1mV | 11.1mV | 8.8mV | Pass |
| 50% Load | 25.0mV | 7.3mV | 11.9mV | 13.1mV | Pass |
| 60% Load | 29.1mV | 7.7mV | 12.4mV | 13.2mV | Pass |
| 70% Load | 32.1mV | 8.8mV | 15.2mV | 14.7mV | Pass |
| 80% Load | 36.5mV | 8.7mV | 15.2mV | 17.1mV | Pass |
| 90% Load | 43.1mV | 10.0mV | 15.3mV | 19.8mV | Pass |
| 100% Load | 49.4mV | 14.4mV | 19.9mV | 24.9mV | Pass |
| 110% Load | 53.7mV | 14.7mV | 20.1mV | 26.4mV | Pass |
| Cross-Load 1 | 24.6mV | 9.4mV | 12.5mV | 10.3mV | Pass |
| Cross-Load 2 | 52.5mV | 16.6mV | 20.7mV | 25.5mV | Pass |
Ripple suppression at +12V isn't particularly good given today's standards in this category. We'd like to see much lower values (less than 40mV), worst-case.
On the other hand, both minor rails perform significantly better than the +12V rail.
Ripple Oscilloscope Screenshots
The following oscilloscope screenshots illustrate the AC ripple and noise registered on the main rails (+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the screen, the bigger the ripple/noise. We set 0.01 V/Div (each vertical division/box equals 0.01V) as the standard for all measurements.
Ripple At Full Load
Ripple At 110-Percent Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
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