Seasonic M12II 500W Power Supply Review

Output Characteristics


Upon first glance we were a bit disappointed with the way the rails are laid out on this particular power supply. The older M12 500W had quad +12V rails which were each rated at 18A for a total combined output of 38A (456W). Meanwhile, this new M12II 500W makes due with 420W (35A) which means it has LESS available power on the +12V rails than the outgoing unit. Why Seasonic decided to reduce the +12V output is beyond understanding but we would have much preferred to have seen at least dual 18A +12V rails. Since the +12V rails are what powers your most important components, these are the ones we are focusing on but from looking at the outputs, it seems that the other rails have received good output allotments as well.

As it stands, the +12V rails should be enough to provide a mainstream system with sufficient power but it will be a close thing, especially if you want to run a mid-range (9600GT or HD3850) dual GPU setup.


Interior Impressions


Yes folks, this interior design should look familiar to those of you who have been hanging around Hardware Canucks for the last year or so. This is the exact same Seasonic design which Antec is using for their Earthwatts 500W power supply and when we reviewed it we came away with a pretty positive impression. You can also see here that the PCB is significantly smaller than the housing; it is actually stunning how small and compact the PCB is considering the output specification of this unit. They say good things come in small packages and Seasonic has loaded this one up with some extremely high-quality components. Let’s take a closer look…


The primary capacitor is a single Hitachi 330uF affair which is rated at 105*C. It is in the capacitor department where this unit differs quite a bit from the Antec Earthwatts: where the Earthwatts used a slightly lower grade combination of a single 85*C Nippon Chemi-Con primary cap and OST secondary units, the M12II uses the aforementioned industrial-rated Hitachi and a sea of Nippons on the secondary side.


The design and construction of the modular interface is a lesson in perfection with extremely well done soldering traces between the internal cables and the connectors of the modular interface. In our tenure here at Hardware Canucks, we have seen some ridiculously shoddy soldering on modular interfaces but this one is done to near perfection.

It is also good to see that all of the non-modular cables are sleeved all the way into the M12’s housing and then the opening in the housing is additionally protected by a rubber grommet.