Introduction

We would like to thank Seasonic for supplying the review sample.




Seasonic decided it was time to refresh all of their high-end platforms, so their new Platinum units now feature "XP3" in their model numbers while the fresh X-1050 and X-1250 units use "XM2". The latter are classified a little below the Platinum units in Seasonic’s portfolio; however, they cost less and offer very good performance since the differences to Seasonic's flagship Platinum models are miniscule.

The X-1250 XM2 (or SS-1250XM2) we will review today is currently among Seasonic's strongest offerings. Strangely enough, Seasonic hasn't yet released a unit with a greater capacity, although the company is considered one of the best and most experienced PSU manufacturers around. Seasonic apparently doesn't believe in such high capacity units and avoids spending precious R&D resources on them; however, 1.3-1.5 kW PSUs were quite popular while the mining craze was at its peak, and we believe that they should at least release one Platinum or Titanium 1.5 kW unit to send the competition that thrives on such monstrous-capacity units a message (see the new Super Flower 1.6 kW unit and the mighty Corsair AX1500i).

Today’s star, the SS-1250XM2, features Gold efficiency that is actually closer to Platinum, a fully modular cabling design, a single +12V rail, and a rather small 120 mm fan. We think Seasonic should use a different approach to cooling by equipping their high-end units with larger fans since these can push the same amount of air at lower speeds for less noise. More and more people are lately making low-noise PC components their prerogative, so it would be wise of Seasonic to also take the lead there as their high-wattage units definitely aren't silent enough as of yet when compared to the competition.

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.

Packaging

The box is large and features a serious graphic with a dark backdrop. At the front are a small photograph of the PSU and the small Golden badge right next to it. The series name is also easily distinguishable thanks to the large yellow "X".


On one of the two sides is a table with the unit's technical and power specifications, and the other side holds a photograph of the fully modular panel and the 80 Plus Gold badge.


The most interesting things on this side are the badges that depict the unit's 80 Plus Gold, Nvidia SLI, ErP Lot 6 2013, and Intell Haswell ready certifications.


A multilingual features description is given on this side.


On the rear of the box are an interesting photograph of the unit's internals and some paragraphs which describe its most crucial features. These include the DC-DC converters on the modular PCB for reduced energy losses, the dual-copper bars that transfer power to the aforementioned PCB, and a mention of the high quality electrolytic and polymer caps used in the platform. A graph on this side also depicts the fan's operation in its normal and in semi-passive modes.

Contents

The outer sleeve hides a sturdy cardboard box with Seasonic's logo on it. Inside, the PSU is well-protected by two thick pieces of packing foam.


The unit is inside a luxurious velvet bag.


The bundle is rich and includes several zip ties, some Velcro straps, a set of fixing bolts, the user's manual, a nice case badge, and a pretty thick AC power cord.


A nice and large pouch stores all modular cables.