Review: Seasonic Platinum Series Fanless 400FL2 400 Watt [SS-400FL2 F3]

The Seasonic Platinum Series Fanless 400FL2 400 Watt [SS-400FL2 F3] power supply belongs to the Platinum series, meeting the requirements of 80 PLUS Gold and being the youngest model of the series. Belonging to 80 PLUS Gold means that the unit has a very high efficiency, which does not fall below the mark of 90% in almost the entire range of loads.

The younger series power supply units (which include both the Seasonic Platinum Series Fanless 400FL2 400 Watt reviewed in this article) are unique because they have a completely passive cooling system, they do not create any noise during operation. However, the manufacturer notes that the power supply should be operated in a case with normal ventilation.

You can buy Seasonic Platinum Series Fanless 400FL2 for the price 108,90 €. Don’t forget to use discount coupon on computeruniverse.netFWNNROU (How to use it?).


Platinum 400 Fanless
AC Input Voltage: 100 V – 240 V
Current: 6 – 3 A
Frequency: 50 Hz – 60 Hz
DC Output Rail +3.3 V +5 V +12 V -12 V +5 VSB
Maximum Power 20 A 20 A 33 A 0.5 A 2.5 A
125 W 396 W 6 W 12.5 W
Total continuous power 400 W
Platinum 400 Fanless Technical Specifications
80PLUS® Platinum
Form Factor Intel ATX 12 V
Dimensions 150 mm (W) x 160 mm (L) x 86 mm (H)
Fan Information Fan Size NA
Fan Control NA
Fan Bearing NA
Life Expectancy NA
Cable Information Modularity Fully Modular
Cable type Flat black cables
Electrical Features Operating Temperature 40 °C
MTBF @ 25 °C, excl. fan 150,000 hours
AC Input Full Range
Protection OPP, OVP, UVP, OCP, OTP, SCP
Safety and Environmental Safety and EMC cTUVus, TUV, C-tick, Gost-R, CB , BSMI, CCC, CE, FCC,
Environmental Compliance Energy Star, RoHS, WEEE, ErP Lot 6, REACH
Warranty 7 Years
Packaging information
Units per carton 4
Individual carton size 330 (L) x 130 (W) x 195 (H) mm
Shipping carton size 545 (L) x 215 (W) x 360 (H) mm


Connector Connector Count Lengths
MAIN-POWER-24-20-PIN-A 1 610 mm – modular
PCIE-8-PIN-A 1 650 mm – modular
PCIE-6-8-PIN-1-A 2 600 mm – modular
600 mm – modular
SATA-5-PIN-A 6 400 + 120 + 120 + 120 mm – modular
300 + 120 mm – modular
PERIPHERAL-4-PIN-A 5 400 + 120 + 120 mm – modular
300 + 120 mm – modular
FDD-4-PIN-1-A 1 101 mm – modular

Power supply init’s kit is:

  • directly Power Supply Unit packaged in a special bag;
  • power cord;
  • screws for fastening;
  • modular cables in a small purse;
  • clamps, ties for wires with velcro;
  • sticker with company logo;
  • user’s manual.

Main Features

  • 80PLUS PLATINUM Certified Super High Efficiency Seasonic DC Connector Module with Integrated Voltage Regulator Module DC to DC Converter Design
  • Active Power Factor Correction (99% PF Typical) High +12V Output
  • Ultra Ventilation (Honeycomb Structure) Full Modular Cabling Design All-in-One DC Cabling Design Easy Swap Connector
  • Total Power: 400 W Power Factor Correction: Active PFC, 99% typical Safety: CB, cTUVus, CCC, TUV, GOST-R, BSMI, CE, UKR, FCC, C-tick
  • Input Voltage: Full Range – 100 ~ 240V (Max. 90 ~ 264V) Input Frequency Range: 50 – 60 Hz
  • Input Current: 6 – 3A MTBF: >100,000 Hours
  • Conductive Polymer Aluminum Solid Electrolytic Capacitors

Review of Seasonic Platinum Series Fanless 400FL2 400 Watt [SS-400FL2 F3]

At the heart of the Seasonic Platinum 400 Fanless is the platform of the “platinum” power supply unit Seasonic Platinum-1000 with improvements in the low-voltage part. The layout of the elements also went to the younger brother in inheritance.

The power supply uses components from Japanese manufacturers, for example, the capacitors are made by the Japanese company Hitachi AIC, and the well-known Japanese company United Chemi-Con is responsible for the “capacity” with liquid electrolyte.

The power supply has a whole range of protections, including overheating protection. A thermal sensor attached to the radiator in the low-voltage part is responsible for this.

The Seasonic Platinum 400 Fanless power supply uses a double-layer PCB, which reduces various network interference and noise generated by the operation of the keys of the power supply itself.

80 PLUS®Platinum

The higher the level of efficiency of the power supply, the less power gets wasted in the form of excess heat . The 80 PLUS® Platinum certification guarantees greater than 90 %, 92 % and 89 % efficiency at 20 %, 50 % and 100 % operating loads, respectively. The Seasonic Platinum Series represents the highest level of technology and efficiency achievement of Sea Sonic during its 40 years of commitment to engineering excellence.


Cooling fans inside the power supply are replaced by passive cooling based on heat dissipation. Silent operation does not only provide a more pleasant working environment but it also results in less power consumption and lower utility bills.

DC to DC Converter Design

The step down DC to DC converter design allows the power supply to be able to serve system components with various voltage needs. Not only is it a flexible, clean voltage conversion solution but it also maximizes the 12 V DC rail output, delivers superior dynamic response and , ultimately, provides for greater system stability.

7 Years Warranty

Our commitment to superior Seasonic quality.

Testing of Seasonic Platinum Series Fanless 400FL2 400 Watt [SS-400FL2 F3]

Cross load characteristics

Tests showed deviations ranging from -1% to + 2%, which can be considered an excellent result.

PFC changes depending on system load. The table shows,  when the load reached 200 W – the coefficient was 0.95, while the maximum value (0.97) was recorded at 400 W level of load.

Load, W 50 80 150 200 250 300 350 400
Loading*,% 13 20 38 50 63 75 88 100
PFC 0,72 0,82 0,89 0,95 0,95 0,96 0,96 0,97

Test: efficiency

With loads of 20%, 50% and 100% of the rated power, the efficiency of the power supply exceeds 90%, 94% and 91%, respectively.

Test: Cooling system and temperature

In conditions of normal ventilation inside the system unit, the temperature of all the main nodes is not only in the normal range, but also far from the critical point.

Test: Power consumption in idle and in sleep mode

In this test, the power supply confirmed its high energy efficiency, not only during operation, but also in sleep mode.

Power Supply Unit Power consumption mode, W
Sleep Power Off
Seasonic Platinum 400 Fanless 6 2
Seasonic X-560 7 3
Seasonic SS-550HT 9 4

Customer reviews, advantages and disadvantages

In their reviews, customers praised the high efficiency of the power supply unit, high-quality component base (Japanese Hitachi AIC capacitors and Nippon Chemi-Con), modularity, a large margin of safety and completely silent operation (no squeaking and noise). Delight caused an increased warranty period, which is 7 years (instead of 5 years, like previous fanless models). Some users praised the good equipment, excellent marking of cables and ease of connection.

To the disadvantages of the buyers attributed the price, a fairly rigid power cable to the motherboard. Also, the disadvantages include the fact that it will be impossible to connect more than one video card to the configuration with this unit. If you plan to use a “top-end” video accelerator, then you cannot do it without an adapter.

first unit was not even quiet.

Second is dead silent. September 17, 2014 Verified Purchase Like most people considering this, I purchased this (rather expensive) item because I expected it to be quiet. With an older build including a GA-P55A-UD3 and an i7 860 the PSU makes a very noticeable whine or hum. I can easily hear it from 6 feet away without trying. I’ve spent a lot of time and money making my systems quiet. I had a fileserver that had a PSU with a failing fan (actually, that was a seasonic too..) – I removed my seasonic x650 from my primary workstation and put it in my fileserver, and then replaced my x650 with this. I know for a fact that the machine I installed this into never exceeds about 120 watts, and is more typically around 67, so, 650 was overkill. The x650 was actually silent though. In my workstation, with an SSD, and undervolted, quiet fans this PSU is easily the loudest component. For the few people interested – the conversion from a first gen x650 to this wasn’t just unplug the cables – both the MB cable as well as the CPU cable have changed on the PSU side. Furthermore, the modular cables on this are not as nice as those provided with my first gen x650 (with mesh and heat-shrink) – these are just plain cables. Now, I’m in my late 30s and have very good hearing. I suspect that this sound might not be noticed by people with average hearing of the same age, or who are older. That being said, I’d avoid it if you’re a silence enthusiast. Additionally, the sound that it does make isn’t a mild “woosh” like that of a fan – it’s a coil or capacitor hum or whine – it’s awful. I have requested a replacement and will update this with the results from that unit. Update: The new unit is entirely silent, even with my ear directly to it with it running it makes no noise. Increasing rating accordingly.

Customer review from Amazon

Silent, but lasted less than (3 years)

This power supply gets high marks for noise; mine is completely silent. I consider this quite an expensive power supply, so I expected top notch quality. At about the 2.5-year mark when I turned on my computer this unit crackled loudly and died. It does have a 7-year warranty, but I could not afford to be down for the week-or-so, the RMA process would take. That meant buying a cheaper interim power supply and spending $13.45 to send the unit back to Seasonic. On the plus side, the unit has a 7-year warranty and Seasonic’s RMA process is pretty clear. They give good directions and provide you with an on-line tracking page so you can see what’s happening. However, at this price point, I do not want my power supply dying every 2+-years. The next time I will not have to buy the interim supply, but I will be out another $13+. I think for anything called the “Platinum” series and sold at this price-point Seasonic needs to provide platinum warranty service. To me, that means sending me a refurbished replacement the day I tell them it failed. Then I can return the faulty unit in the box they sent me the replacement unit in, and slap on the pre-paid label (that includes free pickup). At the very least they should refund the customer incurred shipping fees for returning a defective product. They did confirm that my unit was faulty and sent me a refurbished unit. I’ve installed it, and it works. The actual turn-around time was only five days, but I do have the advantage of only living about 40 miles from the repair depot. Still, with tax, replacement unit, and shipping this power supply has now cost me $194.37.

Customer review from Amazon

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