Seasonic X-400 Fanless Power Supply Review

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Introduction

Seasonic has just released a series of fanless power supplies with the 80 Plus Gold certification, full modular cabling system, and single +12 V rail. They released two models so far: 400 W and 460 W. Let’s take an in-depth look at their 400 W model.

The new X Fanless series shares the same design concepts from the “standard” Seasonic X series, like the use of a resonant switching circuit, the use of a synchronous design in the secondary with DC-DC converters for the +5 V and +3.3 V outputs, the installation of the DC-DC converters directly on the modular cabling system, and some connectors of the modular cabling system soldered directly on the main printed circuit board.

Seasonic X-400 Fanless power supplyFigure 1: Seasonic X-400 Fanless power supply

Seasonic X-400 Fanless power supplyFigure 2: Seasonic X-400 Fanless power supply

The Seasonic X-400 Fanless is 6.3” (160 mm) deep and, as the name implies, it doesn’t have any kind of fan, being a product target to users that want to build the quietest computer possible.

This unit features active PFC, of course.

The new Seasonic X-400 Fanless has a full modular cabling system, meaning that even the main motherboard cable is modular. This system has seven connectors and the power supply comes with the following cables:

  • Main motherboard cable with a 20/24-pin connector, 23.6” (60 cm) long
  • One cable with two ATX12V connectors that together form an EPS12V connector, 25.6” (65 cm) long
  • One cable with one six/eight-pin connector for video cards, 23.6” (60 cm) long
  • One cable with three SATA power connectors, 21.3” (54 cm) to the first connector, 5.9” (15 cm) between connectors
  • One cable with two SATA power connectors, 21.3” (54 cm) to the first connector, 5.9” (15 cm) between connectors
  • One cable with three standard peripheral power connectors, 21.3” (54 cm) to the first connector, 5.9” (15 cm) between connectors
  • One cable with two standard peripheral power connectors, 21.3” (54 cm) to the first connector, 5.9” (15 cm) between connectors
  • One adapter to convert one standard peripheral power connector into two floppy disk drive power connectors

All wires are 18 AWG, except the ones used on the ATX12V/EPS12V  and on the video card auxiliary power cables, which are thicker (16 AWG).

The cable configuration is satisfactory for a 400 W product, and the cables are very long for a 400 W unit.

Seasonic X-400 Fanless power supplyFigure 3: Cables

Let’s now take an in-depth look inside this power supply.

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Author: Gabriel Torres

Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.

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