Voltage Regulation and Quality

+3.3V regulation
Load Voltage
10% +2.24%
20% +2.00%
50% +1.42%
80% +0.80%
100% +0.30%
110% +0.08%

 

+5V regulation
Load Voltage
10% +0.80%
20% +0.60%
50% -0.12%
80% -0.70%
100% -1.29%
110% -1.40%

 

+12V regulation
Load Voltage
10% +2.80%
20% +2.66%
50% +2.30%
80% +1.97%
100% +1.49%
110% +0.54%

Results are measured under room temperature using 115VAC. +12V starts very high since the tests are conformed to ATX standards. As expected, the 12V rail shows low drops and handles up to 41A as well. +3.3V and +5V are well regulated and not too weak. 5V in particular is very stable with only a small difference between 10% and 110% load.

Ripple and Noise

+3.3V ripple quality
Load Ripple and noise
10% 7mV
20% 9mV
50% 14mV
80% 16mV
100% 18mV
110% 22mV

 

+5V ripple quality
Load Ripple and noise
10% 6mV
20% 7mV
50% 8mV
80% 11mV
100% 19mV
110% 21mV

 

+12V ripple quality (worst rail)
Load Ripple and noise
10% 9mV
20% 10mV
50% 14mV
80% 22mV
100% 25mV
110% 29mV

Maybe we should stop measuring ripple and noise for Seasonic products since the results make their opponents angry. We've used up all of the positive words in our vocabulary in other Seasonic articles, so we'll just repeat what we said in the X-460FL review: The voltage quality is absolutely flawless. Small transients are no big deal for 3.3V and 5V, and +12V hardly has any noise at all. In short, this is an excellent design.

Let's Take a Look Inside Noise, Efficiency, and Power Factor
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  • Arbie - Wednesday, March 23, 2011 - link

    Yes, thanks for listing the cable lengths, especially the main power / cpu cable. Last time around I bought an expensive and high-quality PSU which turned out to have main cable so short that it barely worked in a mid-size tower. BTW you say the main cable is 60 cm in one place, and 65 cm in another. Unless I misread it.

    Seasonic is now on my list for the next time.
  • somedude1234 - Wednesday, March 23, 2011 - link

    I used this PSU in my home server build and couldn't be happier. When the server is sitting idle or just serving up media, the PSU fan doesn't run. When the Xeon 3440 is churning through high def video transcodes, the system is still dead quiet.

    I expect this server to last 5-10 years so paying for quality components up front wasn't a problem.
  • poohbear - Thursday, March 24, 2011 - link

    Just wanted to post thank you for buying from a retailer instead of using a cherry picked review sample from the company. I hope you guys do this for all the hardware you review, not just the PSUs. Great to read impartial reviews like this!

    oh, and the article was well done too.;)
  • Martin Kaffei - Thursday, March 24, 2011 - link

    No problem. But we often get samples from a manufacturer, less frequent from a retailer or distributor.

    These are chosen randomly so the manufacturer doesn't know, if we check out the version on the market. Nevertheless I don't have the money to pay for every sample so we still have different sources.
  • ClagMaster - Friday, March 25, 2011 - link

    Excellent article that provides a great deal of insight into the design and construction of the X-Series 560W.

    A good read after a hard day at work.

    For $120 this is a fair price for quality components, an excellent design, and a diverse assortment of connectors of ATX Towers and HTPC's.

    This is a 850W unit which is scaled down to 550W service. I suppose having the fan start above 20% of load is necessary but the fan is indeed very quiet. This power supply has plenty of margin for operation above 550W.

    The only improvement I can think of using a PWM Fan with Hydro bearings.

    Seasonic is a company which stands behind its warranty too. I had a 500W MII power supply go bad 6 months ago. A diode had come lose from its mainboard and lodged in the fan grill. I applied for an RMA, boxed the failed power supply, mailed it to their RMA center in California, and recieved a new replacement in less than two weeks.

    No hassle -- No problems -- Full satisfaction with the service.
  • oneoho - Sunday, March 27, 2011 - link

    This article may have converted me to a Seasonic fanboy :)

    More than I've ever wanted to know about a PSU but definitely got my nerd juices flowing.

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