Voltage Regulation

+3.3V Regulation/Ripple and Noise
Load Voltage
5% +1.28% (5mV)
10% +1.24% (6mV)
20% +1.12% (8mV)
50% +0.24% (10mV)
80% -1.23% (11mV)
100% -1.67% (14mV)
110% -1.79% (14mV)
Crossload +12V max. +0.61%
Crossload +3.3V/+5V max. +0.00%

 

+5V Regulation/Ripple and Noise
Load Voltage
5% +1.20% (7mV)
10% +0.82% (7mV)
20% +0.40% (9mV)
50% -0.02% (11mV)
80% -0.94% (12mV)
100% -0.92% (12mV)
110% -0.86% (13mV)
Crossload +12V max. +0.28%
Crossload +3.3V/+5V max. -0.04%

 

+12V Regulation (Worst Rail)/Ripple and Noise (Worst Rail)
Load Voltage
5% +1.13% (4mV)
10% +1.04% (5mV)
20% +0.98% (22mV)
50% +0.48% (16mV)
80% +0.01% (20mV)
100% -0.31% (24mV)
110% -0.67% (26mV)
Crossload +12V max. -0.17%
Crossload +3.3V/+5V max. +0.13%

Noise Levels

Loudness
Load Opinion
5% low fan noise and small electrical side noise
10% low fan noise and small electrical side noise
20% low fan noise and small electrical side noise
50% fan noise and small electrical side noise
80% strong fan noise and small electrical side noise
100% strong fan noise and small electrical side noise
110% strong fan noise and small electrical side noise

Efficiency and PFC

Efficiency (AC input minus DC output) and Power Factor
Load Efficiency PFC
5% 79.83% 0.712
10% 86.53% 0.898
20% 90.77% 0.942
50% 93.03% 0.979
80% 91.99% 0.988
100% 91.40% 0.989
110% 91.27% 0.990

The ball bearing is (almost) inaudible under high loads. During low loads you might hear the PFC choke if you are close enough, but this shouldn't be a problem when the PSU is mounted in a closed case. If desired the fan can be turned off through up to 40% load by a small switch on the front of the casing, which would make the PSU completely silent at lower loads (other than the electrical noise we noted).

Efficiency is much higher than expected. Seasonic is well above the requirements for the 80 Plus Platinum certificate (90%/92%/89% efficiency at 20%/50%/100% load). Even at lower loads Seasonic is able to surpass most results from competing products. In addition the Platinum Series 860W performs much better than what we saw from the Enermax Platimax 750W. It's only at 5% load that this PSU is below 80% efficiency, and even then it's basically a rounding error. So far this is an exceptionally good result; PFC could be a little better, but we don't want to overdo things.

During all loads voltage regulation is simply perfect. Even under crossload conditions all voltages are close to their optimal values. -1.67% is the "worst" result on 3.3V while 12V is much better (-0.31% as long as we stay at <100% load). Another highlight is the low ripple voltage. We would like to see such results more often, since 26mV on 12V is only 0.22% ripple and noise—according to the ATX specification 1% is allowed. Enermax had no problems with this level as well and makes stable outputs too, but ripple was noticeably higher. Given these results, Seasonic is clearly the winner in our head-to-head comparison.

Internals and Electronics Probably the Best PSU Ever!
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  • Exodite - Friday, February 24, 2012 - link

    Many thanks for an excellent review, the technical details is what keeps bringing me back to AnandTech.

    I'm currently using a Seasonic SS460-FL myself, the 460W X-Series fanless model, and it's been all but perfect. The only issue is what I'd consider the high electrical noise, something the unit shared with the M12 2 800W model it replaced, but it's tolerable in a suitably isolated case.

    Before I scare anyone off by that comment I should note that I'm extremely picky about noise, to the point that I'm running the two 140m fans on my CPU cooler (a Noctua NH-C14) at 750RPM because anything above that is too loud to my taste.

    Like many other posters here I will continue buying Seasonic PSUs for the foreseeable future due to their impeccable quality and performance. Skimping on what's essentially the heart and circulatory system of your computer always struck me as ill-advised.
  • Martin Kaffei - Saturday, February 25, 2012 - link

    Some fanless PSUs had a noisy PFC choke, the source might be magnetostriction. Often a magnetic field is not constant because current changes or other inductivities trouble the choke. This deforms the materials and makes such noises.

    Since there is no fan noise you can hear the electrical noise much better. In truth the electrical noises are at the same level as always.
  • dj christian - Thursday, March 1, 2012 - link

    So you'r running only the CPU-fans? Are the rest passive?
  • kensiko - Friday, February 24, 2012 - link

    Good but did you review the Kingwin (Super flower) ? I saw some reviews and everybody agrees that the components are of high quality.

    I did buy a Kingwin and I class it as good as Seasonic (I owned a Seasonic before)
  • kensiko - Friday, February 24, 2012 - link

    I'm talking about the Lazer Platinum Series for sure.
  • Beenthere - Friday, February 24, 2012 - link

    IME few reviewers consider Super Flower/Kingwin in the same class as Seasonic.
  • palindrome - Friday, February 24, 2012 - link

    You must not read PSU reviews then...
  • Breit - Friday, February 24, 2012 - link

    You say that this 860W model is the best PSU SeaSonic has to offer, but what about the 1000W unit SS-1000XP released in Q4-2011? I thought it is actually the same PSU with higher ratings?! It even has the 80 PLUS Platinum label and also has exceptionally good efficiency over a wide range of loads well above 90% from 20% load to 100% load. I think it should at least get mentioned in the article. The Gold-units from SeaSonic you are referring to were released in 2010 i think.
    Besides that thanks for this very good article, its always a pleasure reading anadtech.
  • Martin Kaffei - Friday, February 24, 2012 - link

    It is fair to say Seasonic made the best current series, but I didn't test the (original) 1KW version yet.
  • Conscript - Friday, February 24, 2012 - link

    You talk about how great they are, but no pics?

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