Voltage Regulation

+3.3V Regulation/Ripple and Noise
Load Voltage
5% +1.52% (2mV)
10% +1.52% (3mV)
20% +1.52% (12mV)
50% +0.91% (11mV)
80% +0.61% (21mV)
100% +0.30% (23mV)
110% +0.30% (25mV)
Crossload +12V max. +1.52%
Crossload +3.3V/+5V max. +1.21%


+5V Regulation/Ripple and Noise
Load Voltage
5% +3.40% (2mV)
10% +3.40% (5mV)
20% +3.20% (12mV)
50% +3.00% (17mV)
80% +2.40% (17mV)
100% +2.40% (20mV)
110% +2.40% (22mV)
Crossload +12V max. +0.20%.
Crossload +3.3V/+5V max. -0.20%


+12V Regulation (Worst Ouput)/Ripple and Noise (Worst Output)
Load Voltage
5% +1.42% (7mV)
10% +0.92% (15mV)
20% +0.75% (25mV)
50% +0.58% (38mV)
80% +0.58% (40mV)
100% +0.92% (47mV)
110% +0.75% (51mV)
Crossload +12V max. +0.42%
Crossload +3.3V/+5V max. +1.33%

Noise Levels

Loudness and Temperatures (Δϑ to 22.1 °C ambient temperature)
Load Opinion
5% choke chirping (1.7 °C)
10% choke chirping (2.6 °C)
20% choke chirping (4.6 °C)
50% choke chirping (8.3 °C)
80% choke chirping (15.9 °C)
100% choke chirping (18.6 °C)
110% choke chirping (20.8 °C)

Efficiency and PFC

Efficiency and Power Factor 115 VAC
Load Efficiency PFC
5% 71.19% 0.879
10% 85.40% 0.911
20% 89.53% 0.958
50% 91.82% 0.988
80% 91.09% 0.991
100% 90.74% 0.992
110% 89.47% 0.993


Efficiency and Power Factor 230 VAC
Load Efficiency PFC
5% 73.67% 0.864
10% 85.86% 0.883
20% 90.10% 0.939
50% 92.14% 0.984
80% 91.60% 0.988
100% 91.06% 0.990
110% 90.84% 0.990

Since there is no fan, there's not much point in measuring sound pressure levels, but what about noise from the electronics? There is an audible "chirping" from the PFC choke and both DC-to-DC converters. However, this could be an individual case. The difference between the ambient and the exhaust temperature is relatively high. We've tested the power supply with a room temperature of just 22.1 °C, which is usually no problem for a high-quality PSU.

The voltage quality is absolutely acceptable. Small transients are no big deal and the smaller rails are always below 25mV which is less than 0.5% ripple. +12V shows only 51mV,  but we should keep in mind that Seasonic had no more than 20mV on all outputs. Overall the voltage regulation is decent. There is hardly any drop on the +12 V and +3.3V rail but +5 V could be closer the optimal value.

Considering the 80 Plus Gold certification, we expected high efficiency and that's exactly what we got. The only blemish is that 5% load "only" comes in at 71-74%. At this point the efficiency could be better than 75%, but we don't want to overdo things.

Internal Design and Components Conclusion
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  • JarredWalton - Friday, April 20, 2012 - link

    I should clarify: sites with referral codes so that you get money from any purchases are clearly spam and will be treated as such. If you link to Newegg for a relevant product and your post has a reason for the link, I'm not going to ban you. But if you have a referral code in there, beware!
  • Iketh - Saturday, April 21, 2012 - link

  • mtoma - Saturday, April 21, 2012 - link

    Mr. Kaffei said: "The AU-500FL has four PCIe connectors—quite nice for a passively cooled PSU".
    Why should this be a good thing? Who puts 2, 3 or 4 video cards in a system with a passive unit? I'm sure that no one, at least of all the targeted market of this unit. I see other manufacturers make similar moves: Seasonic puts two 6 pin connections in his 460W fanless models. I don't see why?
    Perhaps someone care to clarify?
  • Iketh - Saturday, April 21, 2012 - link

    I'm using both 6 pin connections from my seasonic 460w for a 6870... I may not understand your post.

    My system pulls 220w with prime95 running while playing a game (2600k and 6870) using a mild 3.8ghz overclock. I could throw another 6870 in there and still have 140w of headroom.
  • mtoma - Saturday, April 21, 2012 - link

    What I meant was that who uses a powerful video card does not target absolute silence in a computer and I presume the target market of a such power supply is aiming absolute silence. Otherwise, (like you case) you may be better off with a more powerful PSU, in the same money you buy a Seasonic 460W fanless.
  • Iketh - Saturday, April 21, 2012 - link

    That's entirely an incorrect assumption. I do work with my "gaming" rig, and need it as quiet as possible.

    And I would only increase my power consumption if I went with a more powerful p/s because of efficiencies at certain loads. Most of it would be wasted!
  • Martin Kaffei - Saturday, April 21, 2012 - link

    "Who puts 2, 3 or 4 video cards in a system with a passive unit?"
    Under certain conditions a fanless PSU can be useful. This PSU has high output reserves and is able to power most SLI and CrossFire setups. Please take a look at the following link:


    The hole PC with two GTX 680 needs 432W from power grid. The Seasonic X-Series X-660 in this PC has about 90% efficiency so the DC load is just 388.8W and far below the power rating of this PSU. Image the value setups with cheaper GPUs have. Of course cooling will be a problem and GPUs are usually louder than common PSUs, but some users might be interested in using water cooling for their graphics cards. It's a small target group but they would be quite unhappy without these solutions.

    In addition there are more than enough single-chip GPUs with two 6-pin connectors, so two plugs are the minimum for a 400-500W PSU. Another good reason for fanless PSU is that fans are the only moving part in a PSU and very sensitive. Lifetime can be much longer without a fan when installing more powerful components.

    Btw. you don't need to use my last name, Martin is enough.
  • Pappnaas - Sunday, April 22, 2012 - link

    To support Martin's comment:

    From a silencers point of view it even might be worth a try to team up two passivly cooled cards, even if the number of suited modells may be small.

    You might disagree, but that doesn't necessaryly mean your point of view represents all views.
  • szimm - Sunday, April 22, 2012 - link

    Why the arrow-shaped ventilation holes...? Well, I guess it looks fancy depending on your tastes, but it seems like they would have gotten better airflow out of it by by not making the holes that shape. And isn't that the whole point? Maybe they are hoping the hot air will see the arrows and move out of the case...
  • bryanl - Monday, April 23, 2012 - link

    Could you explain this statement in the review?

    "The overall design definelty looks like a Seasonic X-460FL with different caps and no line filtering stage."

    Because I see a line filter in the lower right of the large photo of the interior, attached to the AC socket. If it's not such a filter, what are the differential choke, 2 small disk Y capacitors, and yellow X capacitor?

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