Hot Test Results

The following tables display surprising results about the electrical performance of the Cyonic AU-550x. Even though the filtering of the minor voltage lines is exceptional, with barely any readable figures at all, the 12V line falls far behind. A maximum ripple of 62 mV at full load is definitely not bad, it is a mere half of the 120 mV design limit, but it is not on par with the astounding performance of the other two main voltage lines. Voltage regulation is fairly good, at 1.5% for the 12 V line and about 2.2% for the 3.3V/5V lines.

Main Output
Load (Watts) 111.65 W 277.72 W 414.04 W 548.99 W
Load (Percent) 20.3% 50.5% 75.28% 99.82%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 1.77 3.38 4.41 3.37 6.62 3.32 8.83 3.32
5 V 1.77 5.17 4.41 5.16 6.62 5.07 8.83 5.04
12 V 7.95 12.14 19.86 12.09 29.8 12.03 39.73 11.96

 

Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
12V
CL2
3.3V + 5V
3.3V 1.9% 4 6 6 8 4 8
5V 2.4% 4 6 6 8 4 8
12V 1.5% 18 24 40 62 60 26

We need to mention that this is a PSU rated at 40°C and we perform our testing at temperatures higher than 45°C - we could reduce the ambient temperature of our hotbox testing but we chose not to do so as the results would then not be comparable to those of our previous reviews.

Despite the 40°C temperature rating, higher ambient temperatures do not have a dramatic impact on the electrical performance of the Cyonic AU-550x. The energy conversion efficiency is reduced by about 0.8%, without significant variations across the entire load range of the power supply. Considering the parts that this unit is made of, it is likely that Cyonic just copied the base ATX specifications that dictate a maximum power rating at 40°C and called it a day, even though the PSU can easily output its maximum power at higher temperatures as well.

The internal temperatures of the Cyonic AU-550x increase relatively more than outside the hotbox, but the difference is small and has no effect on the overall performance of the unit. Still, it is apparent that the PSU gets a little hotter than it is supposed to because Cyonic opted for better acoustics performance, forbidding the fan from spinning too fast if the temperatures do not reach critical figures. The heatsinks are also small, even considering the mediocre power output and high efficiency of the unit. Nevertheless, the Cyonic AU-550x maintains tolerable noise figures even in the hellish environment of our hotbox, at the expense of a little higher internal temperatures. 

Cold Test Results Final Words & Conclusion
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  • YoloPascual - Monday, August 17, 2015 - link

    I knew it! The looks and the brand name pertains to one and only OEM.
    Seasonic
    Seonic
    Cyonic
  • DanNeely - Monday, August 17, 2015 - link

    I've noticed this on a few other Seasonic designs, but why do they split the modular 24pin cable into 18+10 pin connectors on the PSU itself?
  • jonnyGURU - Monday, August 17, 2015 - link

    So it fits on the limited real estate available on the modular PCB. And the extra four pins are for voltage sense (why 28 instead of just 24).
  • DanNeely - Monday, August 17, 2015 - link

    OK, Why does it need 4 extra wires for voltage sense though? IIRC the doubled wire on one of the 3.3 pins from the standard layout is for vSense; 2 more cover the +5 and +12V rails. That leaves 2 more unaccounted for. +5VSB and -12V are possible I guess; but for as lightly utilized as they are it seems like overkill to me.
  • Innokentij - Monday, August 17, 2015 - link

    Been loving Seasonic since i got my first PSU from them. Best there is.
  • Beaver M. - Tuesday, August 18, 2015 - link

    My Enermax is 8 years old now, still running strong and the fan is as quiet as on day one.
    I could NEVER say that from a Seasonic, and I used quite a few in PCs and had friends battle with them in their own. One friend had to replace one at the very start, then again after a year and again after 3 years.
  • tamalero - Wednesday, August 19, 2015 - link

    PC Power & cooling here. These units have been top notch all the time.
    Noone of my units have failed. and I'm on the third 750W Silencer series.
  • dananski - Wednesday, August 19, 2015 - link

    Bought a fantastic PSU from Hiper over 8 years ago after reading the review here on AT, and still working wonderfully. In fact I think it has vastly outlived the company.
  • Flunk - Monday, August 17, 2015 - link

    I've learned, over time, that you don't pay attention to the name on the box. It's the OEM that really matters and because of that I'd recommend one of these all day long.
  • jonnyGURU - Monday, August 17, 2015 - link

    That's not the best way to shop since it's not the OEM that supplies the cable compliment, service, warranty, etc. If you buy it and it dies in a year and you can't find who to send the PSU back to or you have to pay $20 to send the PSU to the Netherlands, you start to think how much those things matter.

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