Seasonic X-Series 850 W Power Supply Review

Introduction

Originally released with 650 W and 750 W versions, Seasonic expanded their 80 Plus Gold X-Series to include 560 W, 660 W, 760 W and 850 W versions. Let’s take an in-depth look at highest-wattage model.

Seasonic also has a fanless series based on the X-Series models, aptly called X Fanless. We’ve already reviewed the 400 W version from this other series, and also the 560 W and 650 W versions of the standard X-Series, and all proved to be outstanding products.

Figure 1: Seasonic X-Series 850 W power supply

Figure 2: Seasonic X-Series 850 W power supply

The Seasonic X-Series 850 W is 6.3” (160 mm) deep, with a 120 mm, dual ball bearing, Japanese fan from Sanyo Denki (San Ace 120), just like other members of the X-Series family.

Like all other members of the X-Series family, the new Seasonic X-Series 850 W has a fully modular cabling system, meaning that even the main motherboard cable is modular. This system has 10 connectors and the power supply comes with the following cables:

• Main motherboard cable with a 20/24-pin connector, 23.2” (59 cm) long
• One cable with one EPS12V connector, 25.6” (65 cm) long
• One cable with two ATX12V connectors that together form an EPS12V connector, 25.6” (65 cm) long
• Four cables with one six/eight-pin connector for video cards each, 25.6” (65 cm) long
• Two cables with three SATA power connectors each, 21.6” (55 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two SATA power connectors, 21.6” (55 cm) to the first connector, 5.9” (15 cm) between connectors
• Two cables with three standard peripheral power connectors each, 22” (56 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two standard peripheral power connectors, 22” (56 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

The cables with SATA and peripheral power connectors use 18 AWG wires, but the main motherboard cable, the EPS12V/ATX12V cables and the video card cables use thicker 16 AWG wires, which is always nice to see.

We think that Seasonic should have added more SATA power connectors, since we’ve seen several 850 W power supplies with 12 SATA power connectors around. It would also be nice if this unit had six video card power connectors instead of only four, this way you could install three high-end video cards without needing to use adapters.

Figure 3: Cables

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