Seasonic M12D 850W: DC-to-DC Perfection?

Packaging and Appearance

The power supply comes in a nice package, enclosed by a bubble wrap bag. This is a modular power supply, so the extra cables come with a small bag that you can use to store the extras. You also get a manual and warranty card, which you will want to hang onto since this power supply comes with a five-year warranty.

This is another black power supply, which probably doesn't matter to most users. The power supply doesn't need to be painted at all, but somehow gray power supplies are no longer as desirable, so PSU companies have settled on black as the new standard. As always, the back is perforated to allow air to exhaust from the PSU, but there's a large Seasonic logo next to the AC jack that blocks some of the ventilation. This is nothing to worry about, however, as Seasonic placed the filtering stage right behind this area, shielded by copper plate that would have blocked airflow regardless.

Compared to some competing power supplies, the 120mm fan looks a little small -- lately we've seen 130 and 140mm fans that take up the entire bottom of the PSU. We will look at cooling and noise performance later to see if that makes a difference. The front of the PSU has six sockets for peripheral cable harnesses and two PEG harnesses. As a whole, the PSUs looks very sleek and displays great craftsmanship, which is nothing less than we would expect from Seasonic.

We took the fan grille off and power up the PSU so that you could see what's directly below the fan. We felt the fins on the heatsinks were a little too big, but Seasonic assures us the size was calculated for optimal performance. It's still better than what we've seen with CWT built models, where the fins block most of the airflow resulting in components that often get hotter than necessary. Seasonic leaves plenty of space between the wide fins, so airflow to the components below will not be a problem. Looking at the above image, you can also see that both the primary and secondary heatsinks will get plenty of airflow, so cooling should be very good.