Seasonic X-400FL Platinum 400W Power Supply Review

This new Seasonic PSU touts Platinum efficiency, a fully modular design, and a host of other enthusiast-worthy hardware features that will ring true with those looking for a what might be "the best" 400 watt PSU on the market. For those of you looking to build that truly powerful HTPC, this PSU also offers silent operation.


In the power supply realm, when consumers think of quiet and efficient power supplies one of the first company that comes to mind is Seasonic. Over time, Seasonic has been one of the most prolific brands covered in our reviews and today we have our second crack at a fanless Seasonic branded unit. This review in particular covers Seasonic’s smallest wattage new addition to their fanless lineup of power supplies; the X-400FL Platinum (SS-400FL2 Active PFC F3).

Seasonic is one of the older companies producing consumer power supplies having been founded in 1975 and entering the PC power supply production market in 1980. During that more than 30 years as a company Seasonic has cultivated lines of power supplies that are today some of the standard bearers for efficiency and quiet computing. This focus, and their reputation for quality, has lead to a real explosion in production as Seasonic can be found providing OEM services on various model lines for Antec, Corsair, PC Power and Cooling, and of course under its own Seasonic brand.

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Fanless Wonder Redux

For a long time, Seasonic has been considered by many enthusiasts to be one of the premier manufacturers of quiet power supplies. Oddly though, prior to today’s entry, we have seen just one truly fanless unit from Seasonic (the X-400FL). Today though, we get a second shot at this type of unit and it is again a 400W unit so we should be able to draw some easy comparisons in how things have changed since we saw the last unit. From the outset, the only immediately obvious change in today’s X-400FL Platinum is that it is rated as being more efficient than the previous unit’s 80 Plus Gold rating. However, it has been almost 3 years since we saw that previous unit so there certainly exists the possibility, or perhaps even the hope, that today’s unit does much more than just come in a bit more efficient. Before moving on, let’s see what Seasonic has to say about this unit:

Seasonic Patented DC Connector Panel with Integrated Voltage Regulation Module*

Seasonic’s Patented Fully Modular Design while minimizing voltage drops and impedance, it greatly maximizes efficiency and cooling to enhance overall performance and reliability.

* Patent #: US8.040.686, TW381825, CN1552150, JP3171420.

Patent Pending: US, DE

80+ Platinum

The Platinum Series, certified in accordance to the 80PLUS highest standards, offers the newest technology and innovation for performance and energy savings with up to 92% efficiency and a true power factor of greater than 0.9PF.

Special Features -

1. 80PLUSآ® Platinum Certified Super High Efficiency

2. Full Modular Cabling Design

3. Fanless- 0dBA

4. Patented DC Connector Module with Integrated VRM [Voltage Regulator Module]

5. DC to DC Converter Design

6. Conductive Polymer Aluminum Solid Capacitors

7. Highly Reliable 105آ°C Japanese Aluminum Electrolytic Capacitors

8. Tight Voltage Regulation [آ±2%]

9. Active Power Factor Correction [99% PF Typical]

10. High +12V Output

11. Gold Plated High Current Terminals

12. Dual Sided PCB Layout

13. Ultra Ventilation [Honeycomb Structure]

14. Multi-GPU Technology Support

15. All-in-One DC Cabling Design

16. Easy Swap Connector

17. Universal AC Input [Full Range]

18. 7 Years Warranty

Unlike with the X-400FL launch, there is little that Seasonic has actually said about this unit. So, let’s move on to see what we have to look forward to when we purchase the X-400FL Platinum in terms of documentation, accessories, cable count, rail layout, output characteristics, and general build quality.