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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  • Pappnaas - Friday, April 20, 2012 - link

    but i found no information included about the size of the unit. Would be nice, if the dates could be added.
  • ggathagan - Friday, April 20, 2012 - link

    From FSP's website:
    5.90” (W) x 5.51” (D) x 3.38” (H)

    5.51" is 139.95mm
  • ggathagan - Friday, April 20, 2012 - link

    My apologies, that was the fanned version.
    Looks like 160mm for this version


    Dimensions(L x W x H)mm: 160 x 150 x 86
  • sgtpokey - Friday, April 20, 2012 - link

    What are the dimensions of the PSU 150mm long, 160mm long, or what? This is actually important for those of us with actual experience running fanless pc builds (fot HTPC's).

    Many fanless enclosures have non-standard formats and may have space restirctions when choosing a fanless psu. In my case the "long" PSU of >160mm will not fit in my case, 160mm would work but leaves me no wiggle room and i would prefer a "standard" size of 150mm.
  • ggathagan - Friday, April 20, 2012 - link

    Call it 140mm
  • ggathagan - Friday, April 20, 2012 - link

    Or call me stupid and call it 160mm
  • KTGiang - Friday, April 20, 2012 - link

    My most recent computer component I bought was a fanless PSU. Specifically, it was a Kingwin STR-500 and I don't have a single regret on the purchase. I had no need for a new PSU but I wanted to change the PSU because the "silent" fan was still audible to my ears in a quiet setting. I love that manufacturers are creating more efficient and fanless power supplies for us consumers to choose

    The one positive side effect of having a single fan PC that I had not realized until recently was the fact that I had almost no dust in my tower after 5 months of heavy usage.

    As of right now, my current setup only has 1 Noctua 120mm fan mounted onto a massive Prolimatech cooler. It is on a fan controller that I only turn up when gaming. When idle, the 2 loudest things in my room are the HDD that I have in a removeable bay and the next loudest thing is the power current going through my monitor.

    Hints for making the quietest PC:
    What I found to be most useful in making a "silent" pc is a case that is well ventilated. The cases that are "silent" and are often laced with tons of "noise dampening foam" tend to hold in heat and don't go very well with fanless equipment. I had previously had the Hush from NZXT and I found that the PC ran about 5c warmer when the side panel was on. I am currently using the NZXT Vulcan which has never been touted as a "silent" case but I bought it and removed both of the included fans. Most of the case is covered in a mesh grill that allows for any heat to dissipate out. I had tried to go completely fanless but it wasn't practical when gaming. As my GTS450 is fanless, there would be absolutely no airflow. The solution was to add a single Noctua fan between the GPU and the CPU to have a "push" of air straight up and out of the case. The main OS is on a SSD to eliminate any vibration noise that may come from the HDD. The storage HDD is on a removeable HDD tray so it can be easily disabled when not needed.

    If anyone knows of a quieter fan that has quite a bit of CFM feel free to recommend it. I'd like to find a quieter option if they're available.
  • jwilliams4200 - Friday, April 20, 2012 - link

    I don't know of any fans that are significantly quieter than the Noctua.

    But I thought you might be interested in a HDD silencer that I have tried, the Smart Drive Neo. It is expensive, but it silences your HDD and keeps it cool. It mounts a 3.5" HDD in a 5.25" bay.

  • Iketh - Friday, April 20, 2012 - link


    Please ban this a$$hole.
  • JarredWalton - Friday, April 20, 2012 - link

    Done! Hint: putting in links (even redirected links) to a site that sells something will get your account banned, ScottKPickering.

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