Seasonic X-Series 650W KM3 Power Supply Review

1. Introduction2. Seasonic X-Series 650W KM3 (Bundle & Cables)3. Seasonic X-Series 650W KM3 (External)4. Seasonic X-Series 650W KM3 (Internal)5. Seasonic X-Series 650W KM3 (Super High Res Gallery)6. Testing Methodology & Results7. Closing Thoughts8. View All Pages

The Seasonic X-Series 650W KM3 is nicely finished with thick paint resistant against rough handling. As with the 850W KM3, the unit passed our screwdriver stress test – we run the head down the side of the chassis with a little force. It didn't mark.

The unit measures 160mm x 150mm x 86 mm (LxWxH). It will fit into any mainstream ATX compliant chassis.

The large fan is hidden behind a black honeycomb grill. We will look at the fan in more detail when we crack open the chassis later in the review.

One side of the power supply is vented which helps enhance air flow. There is also a power switch and connector at the side. The Seasonic badge is seen underneath the power port/switch.

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).

Seasonic X-Series 650W Power Supply (KM3)
DC Output	+3.3V	+5V	+12V	-12V	+5Vsb
Max Output	25A	25A	54A	0.5A	3A
Total Power	125W		648W	6W	15W
	650W

54A can be delivered to the +12V rail, which is plenty for two relatively high end graphics cards.

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