First Look: Seasonic M12D 850W PSU

First Look: Seasonic M12D 850W PSU

Manufacturer: Seasonic

I would consider it to be an understatement to say that Seasonic has clearly gone to a lot of trouble to make this PSU. It's been a while since Seasonic released something quite so new without just OEMing for other company's products, and it's making quite a fuss over its new M12D PSU.

At 850W it's the highest wattage PSU Seasonic has ever launched, where as everyone else has chased the four digit threshold that very few people care for, instead the new frontier in PSU technology is efficiency. Seasonic's M12D is rated an impressive 80Plus Silver - achieving 85 to 88 percent efficiency across the 20 to 100 percent load range with a 90 percent upwards PFC.

Seasonic's method of achieving such efficiency is no different than we've seen other high efficiency rated supplies - it uses a DC-DC conversion system for the 3.3V and 5V rails from the main 12V output, instead of having an additional set of full AC-DC power converters. Not only this, but Seasonic is also trying another angle too by giving big marketing kudos to its Sayno Denki fan. Honestly, we're not to surprised about this after having a very interesting conversation with Walter Sun, European Marketing Director at Seasonic - one of his first points about Seasonic PSUs even previous to this was the quality of fans used.

We've not yet had time to get to load this unit ourselves and test it, but we were keen to check out our early sample to see how it compares against the formidable Cooler Master Ultimate UCP 900W and Antec Signature 850W PSUs.


The box is pretty normal although the back has rather "liberal" claims just like the Sesaonic S12II 500W we reviewed a while ago, where every possible "feature" is suggested to be a benefit, instead of just being what is - take the "Ultra Ventilation" honeycomb grill for example. Some of the claims are just untrue because, unless I've been sitting in front of this monitor for far too long, I couldn't see a single solid aluminium capped capacitor directly linked to the 12V rails and there's literally only a couple of them in total inside. Simply apply your BS filter because it's just liberal use of the marketing wand, that's all.


The PSU comes securely packed inside the box with plenty of foam, and included is the power lead, bundle of cables in its own Seasonic branded bag to keep them together, the five year warranty card and user manual.


In our "press pack" we also got a few extra goodies to help explain what we were getting and what results we should be seeing - we got a Chroma test report, ripple testing and the 80Plus certification (that's independent of Seasonic) as well as a guide to the fan statistics too! Seasonic is clearly very serious about its new power supply and keen to prove its worth, and we've included some super sized images so you can read some of the important parts it for yourself.