Seasonic S12D 850W (Page 2 of 4) | Reports

Page 2 - Physical Look - Outside

The Seasonic S12D 850W looks practically identical to its predecessors; with the exception of a few minor details. Starting from the back part of the power supply, we have the same familiar honeycomb mesh design; and the standard on/off switch located to the right of the male connector for power input. The low resistance honeycomb mesh design is implemented to maximize airflow and minimize air resistance. This is done as heat needs to leave the power supply as easily and efficiently as possible, because the Seasonic S12D incorporates only one 120mm fan at the bottom, with no side fans. As with most new power supplies, the Seasonic S12D has an automatic full range (100V-240V) AC line voltage selection, so the user does not have to worry about manually selecting input voltage.

Generally speaking, if you are installing your Seasonic S12D power supply into a windowless case, it is almost impossible to distinguish what Seasonic power supply model you have installed, haha. You may find the Seasonic M12II 500W we've reviewed last year to be pretty familiar from this angle!

Residing behind the eight-ring fan grille; again, designed for minimal air resistance while providing adequate protection -- is the primary and only cooling fan installed. The 120mm fan draws air from the bottom of the power supply over its internal components for cooling. Exhaust heat is allowed to leave at the back of the power supply through the large mesh opening as aforementioned.

Measuring 14cm long, our Seasonic S12D 850W is even identical in dimensions to previous Seasonic self-branded line of power supplies; including the S12, S12II, M12, M12II, and the M12D. The short length proves to be very valuable in cases with limited space to work with. It's actually very impressive for Seasonic to design a power supply rated up to 850W power output -- and we know that if Seasonic rates it to be 850W, we are confident that we can actually get it in real world tests -- to be exactly the same size as its lesser powered cousins. Meanwhile, four screws on each side of the S12D secure the power supply case together; where one side has a warranty seal on -- so you can't open the power supply without voiding the warranty. However, you can still remove four separate screws that attach the fan grille to the power supply casing to clean the fan without voiding the warranty.

As you probably have already noticed by now, the Seasonic S12D has the same subtle design as it's always been in the past -- no fancy colors, no fancy LEDs. And there's no need for such either. The black matte finish of the power supply evokes a sense of elegance and cleanness on its own, and we've always liked it for what it is. Since the S12D is non-modular, all cables are fixed to the unit. Many power supply purists prefer fixed cables because it delivers power with lower loss compared to modular units. The reason behind this is because it eliminates one connector between the source and point of delivery. The cost of this advantage is cabling convenience.

A C-shaped opening on the right side of the power supply (From the angle above) means that in a typical configuration, the cables leave the power supply at the end near the inside panel of your case. By doing this, it makes clean cabling a little easier for the user. The lead out is done cleanly from this angle, and all cables are properly sleeved and strapped together at this point.

The external build quality of Seasonic's S12D 850W power supply is excellent as always. Fit is done well with minimal panel gaps, and all edges are nicely finished off. It's the level of refinement both engineering and build that we'd always expect from the company, and we believe that they have done a commendable job with regards to the external build quality. We'll crack open the power supply to see what's inside in the following section too.

That is subtle. Nicely done, yo. - Editor

The voltage specification label on the side of the Seasonic S12D. There are two virtual rails. Up to 24A can be delivered via the +3.3V rail for a total of 79.2W; while 30A is available on the +5V rail for 150W output. The total combined output for the +3.3V and +5V rail is also 150W. This means that your power allocation combination must fall within the limits of the listed specifications. Meanwhile, each of the two +12V rails can provide up to 40A for a total of 840W combined -- very impressive. Overall, the combined power output is... well, 850W haha. Again, your power distribution in your system must fall within the limits provided -- it must not exceed 79.2W on the +3.3V rail, 150W on the +5V rail and 150W combined for both, 480W on the +12V rails up to 840W combined, and 850W combined between the +12V and +3.3/+5V rails. It does sound a bit confusing to understand how this works at first, but generally speaking this configuration allows very flexible power demands and should be sufficient to accommodate most users.

The Seasonic S12D 850W is 80 Plus Silver certified, which means that it is certified to be at least 85%, 88%, 85% efficient at 20%, 50%, and 100% load, respectively.

Every cable attached to the Seasonic S12D power supply is fully sleeved for aesthetics and cabling convenience. As far as the connectors go, they connect securely and don't feel cheap at all -- but when you need to disconnect them, the clips are easy to unlatch. These cables are all decently long, I've had no problems installing the power supply on a bottom chamber design or a standard top implementation -- the cables have the necessary length to reach where power is needed, even in a full tower chassis. The cables are designed so that you cannot plug them in the wrong orientation or direction. The following connectors are available out of the box from the S12D:

- 1x ATX 24-pin
- 1x EPS 8-pin
- 1x ATX 4+4-pin
- 2x PCIe 6-pin (2 cables)
- 2x PCIe 6+2-pin (2 cables)
- 6x Molex (2 cables)
- 1x FDD 4-pin (End of one of the Molex cables)
- 9x SATA (3 cables)

It isn't a typo that there's an ATX 4+4-pin and an EPS 8-pin block. The ATX 4+4-pin can be used as a secondary 8-pin connector for server class motherboards.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion