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Advanced Transient Response Tests
For details about our transient response testing, please click here.
In the real world, power supplies are always working with loads that change. It's of immense importance, then, for the PSU to keep its rails within the ATX specification's defined ranges. The smaller the deviations, the more stable your PC will be with less stress applied to its components.
We should note that the ATX spec requires capacitive loading during the transient rests, but in our methodology, we also choose to apply a worst case scenario with no additional capacitance on the rails.
Advanced Transient Response at 20% – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.103V | 11.971V | 1.09% | Pass |
| 5V | 5.026V | 4.898V | 2.55% | Pass |
| 3.3V | 3.371V | 3.228V | 4.24% | Pass |
| 5VSB | 5.072V | 5.017V | 1.08% | Pass |
Advanced Transient Response at 20% – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.104V | 11.926V | 1.47% | Pass |
| 5V | 5.024V | 4.874V | 2.99% | Pass |
| 3.3V | 3.372V | 3.206V | 4.92% | Pass |
| 5VSB | 5.073V | 5.025V | 0.95% | Pass |
Advanced Transient Response at 20% – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.106V | 11.885V | 1.83% | Pass |
| 5V | 5.025V | 4.879V | 2.91% | Pass |
| 3.3V | 3.371V | 3.185V | 5.52% | Pass |
| 5VSB | 5.074V | 5.021V | 1.04% | Pass |
Advanced Transient Response at 50% – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.077V | 11.962V | 0.95% | Pass |
| 5V | 5.018V | 4.883V | 2.69% | Pass |
| 3.3V | 3.364V | 3.213V | 4.49% | Pass |
| 5VSB | 5.036V | 4.980V | 1.11% | Pass |
Advanced Transient Response at 50% – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.079V | 11.930V | 1.23% | Pass |
| 5V | 5.019V | 4.862V | 3.13% | Pass |
| 3.3V | 3.364V | 3.191V | 5.14% | Pass |
| 5VSB | 5.037V | 4.984V | 1.05% | Pass |
Advanced Transient Response at 50% – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.080V | 11.925V | 1.28% | Pass |
| 5V | 5.019V | 4.865V | 3.07% | Pass |
| 3.3V | 3.363V | 3.154V | 6.21% | Pass |
| 5VSB | 5.038V | 4.981V | 1.13% | Pass |
The transient response at +12V is satisfactory, but the competing offerings perform better. The situation remains the same, with the other rails.
Turn-On Transient Tests
In the next set of tests, we measure the PSU's response in simpler transient load scenarios—during its power-on phase. Ideally, we don't want to see any voltage overshoots or spikes since those put a lot of stress on the DC-DC converters of installed components.
The performance is good here. The only things we notice are a tiny spike at 5VSB and a small step in the "PSU OFF to Full 12V" test.
Ripple Measurements
Ripple represents the AC fluctuations (periodic) and noise (random) found in the PSU's DC rails. This phenomenon significantly decreases the capacitors' lifespan because it causes them to run hotter. A 10-degree Celsius increase can cut into a cap's useful life by 50%. Ripple also plays an important role in overall system stability, especially when overclocking is involved.
The ripple 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 | 7.1 mV | 6.7 mV | 14.0 mV | 8.0 mV | Pass |
| 20% Load | 7.4 mV | 8.9 mV | 15.0 mV | 8.6 mV | Pass |
| 30% Load | 8.7 mV | 12.7 mV | 18.0 mV | 9.6 mV | Pass |
| 40% Load | 10.7 mV | 9.7 mV | 18.7 mV | 10.7 mV | Pass |
| 50% Load | 20.0 mV | 10.6 mV | 19.0 mV | 12.2 mV | Pass |
| 60% Load | 15.0 mV | 12.1 mV | 20.4 mV | 13.5 mV | Pass |
| 70% Load | 18.4 mV | 13.0 mV | 23.0 mV | 14.4 mV | Pass |
| 80% Load | 21.4 mV | 15.1 mV | 24.1 mV | 17.0 mV | Pass |
| 90% Load | 24.5 mV | 14.8 mV | 27.5 mV | 17.3 mV | Pass |
| 100% Load | 36.7 mV | 16.2 mV | 29.8 mV | 20.8 mV | Pass |
| 110% Load | 32.5 mV | 15.6 mV | 28.2 mV | 20.0 mV | Pass |
| Crossload 1 | 12.1 mV | 14.8 mV | 20.2 mV | 12.5 mV | Pass |
| Crossload 2 | 33.6 mV | 15.2 mV | 27.0 mV | 18.2 mV | Pass |
Strangely enough, the ripple suppression at +12V with 110% load is a little better than with full load, at the same operating temperature. This is something that we don't see every day.
The ripple suppression is satisfactory at +12V since it stays below 40mV. On the 5V and 5VSB rails, ripple is low, while we would like to see a little lower readings at 3.3V.
Ripple At Full Load
Ripple At 110% Load
Ripple At Cross-Load 1
Ripple At Cross-Load 2
EMC Pre-Compliance Testing – Average & Peak EMI Detector Results
Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other close-by devices.
Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other close-by devices if too high. For example, it can be the cause of increased static noise in your headphones or/and speakers.
The EMC performance is mediocre. Lots of high spurs that exceed the corresponding limits, in the lower frequency range.
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