Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.
Transient Response Tests, Ripple Measurements and EMC Pre-Compliance Testing
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 extra capacitance on the rails.
Advanced Transient Response at 20% – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.242V | 12.146V | 0.78% | Pass |
| 5V | 5.022V | 4.890V | 2.63% | Pass |
| 3.3V | 3.329V | 3.130V | 5.98% | Fail |
| 5VSB | 5.067V | 4.999V | 1.34% | Pass |
Advanced Transient Response at 20% – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.241V | 12.114V | 1.04% | Pass |
| 5V | 5.021V | 4.865V | 3.11% | Pass |
| 3.3V | 3.329V | 3.091V | 7.15% | Fail |
| 5VSB | 5.067V | 4.989V | 1.54% | Pass |
Advanced Transient Response at 20% – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.241V | 12.132V | 0.89% | Pass |
| 5V | 5.021V | 4.861V | 3.19% | Pass |
| 3.3V | 3.328V | 3.091V | 7.12% | Fail |
| 5VSB | 5.068V | 5.014V | 1.07% | Pass |
Advanced Transient Response at 50% – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.211V | 12.117V | 0.77% | Pass |
| 5V | 5.015V | 4.876V | 2.77% | Pass |
| 3.3V | 3.322V | 3.112V | 6.32% | Fail |
| 5VSB | 5.025V | 4.959V | 1.31% | Pass |
Advanced Transient Response at 50% – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.211V | 12.092V | 0.97% | Pass |
| 5V | 5.014V | 4.849V | 3.29% | Pass |
| 3.3V | 3.322V | 3.074V | 7.47% | Fail |
| 5VSB | 5.025V | 4.956V | 1.37% | Pass |
Advanced Transient Response at 50% – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.211V | 12.082V | 1.06% | Pass |
| 5V | 5.014V | 4.850V | 3.27% | Pass |
| 3.3V | 3.322V | 3.075V | 7.44% | Fail |
| 5VSB | 5.025V | 4.964V | 1.21% | Pass |
The +12V rail, the most significant of all, performs well. This is not the case though for the minor rails and especially for the 3.3V rail, which fails in all of our tests. The V1300 also had a problem here, in the minor rails, so Cooler Master should ask Delta to improve the DC-DC converters that generate 5V and 3.3V.
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.
Only a small voltage overshoot at 5VSB, which is nothing to worry about.
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 degrees 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 | 12.5 mV | 15.0 mV | 15.7 mV | 12.5 mV | Pass |
| 20% Load | 13.0 mV | 15.9 mV | 15.1 mV | 12.8 mV | Pass |
| 30% Load | 16.1 mV | 16.3 mV | 16.5 mV | 13.3 mV | Pass |
| 40% Load | 18.4 mV | 16.6 mV | 17.7 mV | 13.8 mV | Pass |
| 50% Load | 19.0 mV | 18.6 mV | 18.0 mV | 13.5 mV | Pass |
| 60% Load | 20.2 mV | 17.8 mV | 17.9 mV | 15.0 mV | Pass |
| 70% Load | 17.3 mV | 20.1 mV | 19.2 mV | 15.2 mV | Pass |
| 80% Load | 19.9 mV | 19.9 mV | 19.6 mV | 17.6 mV | Pass |
| 90% Load | 20.9 mV | 23.0 mV | 21.0 mV | 16.9 mV | Pass |
| 100% Load | 25.3 mV | 23.4 mV | 22.3 mV | 18.7 mV | Pass |
| 110% Load | 26.9 mV | 24.1 mV | 24.3 mV | 19.5 mV | Pass |
| Crossload 1 | 14.4 mV | 20.7 mV | 21.9 mV | 13.9 mV | Pass |
| Crossload 2 | 25.5 mV | 23.3 mV | 19.1 mV | 17.6 mV | Pass |
The ripple suppression is decent, but not even close to the results of other high-end units with similar price tags. Delta's platforms used to be an example to follow when it comes to ripple suppression, but clearly this is not the case anymore because the competition has been vastly improved.
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 conducted EMI emissions are kept low. The corresponding filter does a good job.
MORE: Best Power Supplies
MORE: How We Test Power Supplies
MORE: All Power Supply Content
HDMI 2.2 is set to debut at CES 2025 — the new standard brings higher resolutions, refresh rates, and bandwidth
AI GPU clusters with one million GPUs are planned for 2027 — Broadcom says three AI supercomputers are in the works
Samsung's 990 Evo Plus SSD matches its recent Black Friday and Cyber Monday sale price - massive 4TB capacity for $239
