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Transient Response Tests
For details on our transient response testing, please click here.
Advanced Transient Response Tests
In these tests, we monitor the response of the PSU in two different scenarios. First, a transient load (10A at +12V, 5A at 5V, 5A at 3.3V and 0.5A at 5VSB) is applied to the PSU for 200ms while the PSU is working at 20 percent load. In the second scenario, the PSU is hit by the same transient load while operating at 50 percent load. In both tests, we use our oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain within the ATX specification's regulation limits.
These tests are crucial since they simulate the transient loads a PSU is likely to handle (such as booting a RAID array, an instant 100-percent load of CPU/GPUs, etc.). We call these tests "Advanced Transient Response Tests," and they are designed to be tough to master.
|Advanced Transient Response 20%|
|Advanced Transient Response 50%|
In the first test, the PWM operation of the main switchers causes a significant deviation on the +12V rail. However, in the second test, the corresponding deviation drops to normal levels for a high-end, 1200W PSU. In general, this power supply yields a decent performance. But it still lags behind most of the competition in this category.
Below are the oscilloscope screenshots we took during Advanced Transient Response Testing.
Transient Response At 20-Percent Load
Transient Response At 50-Percent Load
Turn-On Transient Tests
We measure the PSU's response in simpler transient-load scenarios — during the power-on phase of the PSU — in the next set of tests.
For the first measurement, we turn the PSU off, dial in the maximum current the 5VSB can output and then switch on the PSU. In the second test, we dial the maximum load +12V can handle and start the PSU while it's in standby mode. In the last test, while the PSU is completely switched off (we cut off power or switch the PSU off by flipping its on/off switch), we dial the maximum load the +12V rail can handle before switching the PSU on from the loader and restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and it is 5.5V for 5V).
Our equipment catches a minor spike at 5VSB, which is nothing to worry about. During the Standby to Full 12V test, the slope is smooth enough. However, in the third test, we notice large ripples on the waveform before the rails settle down to the nominal voltage level.
Current page: Transient Response TestsPrev Page Cross-Load Tests And Infrared Images Next Page Ripple Measurements
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Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.
Thank you for the read. Did you know that the power feeding this PSU can instead be fed into 3 normal sized machines? The power of choice is yours to make, but electricity will not be infinite.Reply
Now THAT is a detailed review!Reply
Teapo capacitors are a hit and miss. I'd say if your running it 24/7 as a coin mining machine with high load it would not last 10 years. For normal use with a few hours gaming per day it might be ok, but 10 years is a long shot for even the best capacitors not to have some degradation.Reply
Can we have some reviews of really high quality 300-600W PSUs? You know the ones that 90% of us here would actually use/need.Reply
Thank you for the read. Did you know that the power feeding this PSU can instead be fed into 3 normal sized machines? The power of choice is yours to make, but electricity will not be infinite.
Did you know that anyone who cares about this PSU, isnt going to be thinking about the 3 400w HTPCs that it could run. Keep your politics out of a PSU review lol.
I will review mid-level and mainstream PSUs as well, no worries about this.Reply
Always nice to see reviews of the high end stuff but really the 300-850watt range will cover the needs of 99% of readers of the side.Reply
Now lets see if Andyson can follow up and start putting out decent lower power units.
Andyson, the notorious RAIDMAX OEM. Not sure any sane person would pick you for a high end PSU, but thanks for trying.Reply
Can we have some reviews of really high quality 300-600W PSUs? You know the ones that 90% of us here would actually use/need.i disagree, can we get a roundup of complete rubbish generic psu's like low end radimax and the like and watch them burn! i think it needs to be done to show people what not to buy.
15588307 said:15588123 said:Andyson, the notorious RAIDMAX OEM. Not sure any sane person would pick you for a high end PSU, but thanks for trying.
is it andyson's fault that raidmax wants them to supply cheap PSU?
Yes, absolutely. Same with other OEMs like Channel Well that know how to make good PSUs but instead churn out cost-cutting junk because that's the best contracts that they can win. I am not forgiving when it comes to PSUs.