Seasonic X-Series 850W KM3 Power Supply Review

1. Introduction2. Seasonic X-Series 850W KM3 (Bundle & Cables)3. Seasonic X-Series 850W KM3 (External)4. Seasonic X-Series 850W KM3 (Internal)5. Seasonic X-Series 850W KM3 (Super High Res Gallery)6. Testing Methodology7. Closing Thoughts8. View All Pages

The unit is nicely finished, with thick paint which proves resistant against rough handling. We ran our screwdriver down the side with a little force and it didn't mark at all.

The large fan is hidden behind a strong honeycomb grill, we will check this out later when we open the unit for analysis.

One side of the power supply is vented to help improve air flow. At the side is a power switch and connector. The company branding is seen underneath this.

The KM3 modular panel has changed completely over the last revision. There is now a ‘hybrid' fan switch which you can toggle on or off – the blue sticker alerts you to this initially and should be removed before using the supply. Seasonic have said this is the industries first ‘advanced three phased thermal control'.

The Hybrid Silent Fan Control provides three operational stages:  Fanless, Silent, and Cooling Mode. In addition, there is a switch provided to allow for manual selection between the Seasonic S2FC (fan control without Fanless Mode) and the S3FC (fan control including Fanless Mode).

The power supply looks great from all angles and only measures 160mm x 150 mm x 86 mm (LxWxH), meaning it will fit into any mainstream ATX compliant chassis.

Seasonic X-Series 850W Power Supply (KM3)
DC Output	+3.3V	+5V	+12V	-12V	+5Vsb
Max Output	25A	25A	70A	0.5A	3A
Total Power	125W		840W	6W	15W
	850W

70A can be delivered to the +12V rail, plenty of power on tap for demanding gaming systems.

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