Seasonic X-Series: X-660 Power Supply Review

Seasonic is well known by computer hardware enthusiasts, and for a good reason. It builds some of the best power supplies in the world. Let's see if its new X-Series 660 watt unit is up to our plethora of high heat tests.


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 and today we have our seventh crack at a Seasonic branded unit. This review covers a new revision to Seasonic's X-Series line of power supplies the X-660 (SS-660KM 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 its 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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The X-Series: Once and Future King?

The Seasonic X-660 is the 7th power supply from Seasonic that we have reviewed, and now the 4th power supply from the X-Series. This makes this series perhaps the most widely covered series we have done to date, and this is for a good reason. As yet, we have not been disappointed by Seasonic's initial offerings of this platform or their subsequent modifications and upgrades. So, we generally have a good idea of what to expect from this X-660, but before moving on let's first see if Seasonic has anything new to say about this unit:

The very first full modular multi-output ATX, high-wattage power supply that has ever obtained the 80PLUS+ Gold certification is introduced by Seasonic, this coveted power supply is named "X" and is offered in 560W versions.

Featuring a patent pending design of "DC Connector Module with Integrated VRM", the X Series is set to achieve both near-perfect DC to DC conversion and fully modularized design without compromising efficiency. After a long wait, finally there is a product that delivers the complete package, ultra-high efficiency, greatly improved dynamic response, and customizable cable arrangement that is tailored to meet any individual's needs.

Now that we know what Seasonic expects from this power supply (the same things it expected from the X-560) let's see what we have to look forward to when we purchase the X-660 in terms of documentation, accessories, cable count, rail layout, output characteristics, and general build quality.