Specifications

Efficiency is Gold, and the maximum operating temperature at up to which this unit can deliver its full power continuously is 50°C. The SS-1250XM2 is also Haswell ready and Seasonic says it to feature all by now standardized protection features, including OCP, which is useless in a single +12V rail unit of such high capacity. We don't believe it has OCP, so Seasonic must have made a mistake in its specifications table, but the fact is that such a feature is useless in such a high capacity unit remains as it would actually fulfill the same role as OPP (Over Power Protection).

The cooling fan is rather small for a 1250 W monster, so its noise output won't be all too pleasant at high loads. Seasonic should have used a 140 mm fan instead since it would be a much quieter while providing the same amount or even more airflow. You thankfully have the option to enable a semi-passive operation through a switch Seasonic unfortunately installed into the unit's back. Seasonic also backs this PSU with a hefty seven year warranty, and given its features, its price looks very good.


The single +12V rail is powerful and can deliver over 100 A! The same applies to the minor rails, and the 5VSB rail is powerful enough; however, its maximum current output could have been a little bit higher. 4 A on 5VSB would completely satisfy us in this particular case.

Cables & Connectors, Power Distribution

Seasonic equipped the unit with a ton of connectors, including ten PCIe and two EPS connectors that are available at the same time. The cables are also long enough, and the distance between connectors is good, with the SATA connectors a little closer to each other than the peripheral ones. All connectors use 18AWG wires, which is in line with the ATX spec.

Since this PSU features a single +12V rail, we do not have anything to comment on when it comes time to talk about its power distribution.