Transient Response
Transient response in power supplies refers to how quickly and effectively the PSU stabilizes its output voltage during sudden changes in load demand, such as when a CPU or GPU increases its power draw. It’s measured by the time and voltage deviation during these shifts. A faster, smaller transient response ensures stable power, preventing instability and component damage.
20% Load – 20ms
| Advanced Transient Response 20% - 50 Hz - No Caps | ||||
| Voltage | Before | After | Change | Pass/Fail |
| 12V | 12.079V | 11.933V | 1.21% | Pass |
| 5V | 4.988V | 4.892V | 1.93% | Pass |
| 3.3V | 3.265V | 3.139V | 3.85% | Fail |
| 5VSB | 5.054V | 5.014V | 0.79% | Pass |
50% Load -20ms
| Advanced Transient Response 50% - 50 Hz - No Caps | ||||
| Voltage | Before | After | Change | Pass/Fail |
| 12V | 12.054V | 11.910V | 1.19% | Pass |
| 5V | 4.957V | 4.863V | 1.90% | Pass |
| 3.3V | 3.259V | 3.128V | 4.03% | Fail |
| 5VSB | 5.013V | 4.968V | 0.90% | Pass |
The transient response is mediocre at 12V, and the 3.3V rail failed in both tests, as you can see in the tables above.
Transient Response ATX v3.1 Tests
[Note] For PSUs without a 12+4 pin connector, the maximum applied load for the transient response tests is 150%, rather than 200%.
The PSU passes all ATX v3.1 transient response tests, but the 3.3V rail drops low.
The 12V rail’s performance is not competitive in these tests.
Pages:
The Cybenetics report indicates that this power supply is compliant with ATX 3.1; however, the transient testing results show issues on the 3.3 V rail.
Could you clarify how ATX 3.1 pass/fail determinations are defined in your methodology? Specifically, how are transient deviations on secondary rails, such as the 3.3 V rail, evaluated when concluding overall ATX 3.1 compliance?
Reference:
Cybenetics ATX 3.1 PASS Report
https://www.cybenetics.com/evaluations/psus/2971/
Which transient response results are you referring to? The transient response tests with normal loads, which I do, and without capacitors? These are my tests; they are not included in any ATX spec. I have been conducting these for many years now, and they are there to compare all PSUs with load on all rails directly.
The ATX v3.1 uses an entirely different transient response load scheme, which Cybenetics adopts, to check against this standard.
This standard is open, so you can study it and look at what it says about transient report testing.
based on your experience did unicon caps was better than toshin kogyo or similar with nippon chemicon, rubycon or nichicon ?
I don’t think they are better than the well-known caps, especially the last three brands you mention.
so it’s basically same tier as TK ?
I don’t have a clue unless I check enough capacitors from Unicon and TK
Interestingly, SAMA P uses a different RSY platform and shows excellent results.
Hi, Aris, do you have any idea why BeQuiet lists Cybenetics Gold efficiency and Noise A+ in its marketing materials, when all Pure Power 13 M PSUs achieved Platinum and A++?
Did they change anything after your tests or why?
They can always downgrade the badges, but never upgrade them.
…they certainly can, but what’s the point, from a marketing point of view,
…probably none.
Maybe they’re not sure about the manufacturing tolerances, who knows 👀