When it comes to power supplies for silent computing, there's one name that always comes up: Seasonic. Seasonic was originally an OEM PSU manufacturer, and they had a reputation for producing good quality, high efficiency products. It is unusual for an OEM manufacturer to bring their own products to the market since there are usually several competitors already using the same power supply. That's why it wasn't until 2002 that Seasonic decided to enter the retail market. The first power supplies had some difficulties: they came in a grey housing, there were no cable sleeves, and in contrast to many other high-end power supplies at the time there were no LEDs (Gasp!). All that customers got was a very simple looking power supply with limited to no features. The fact that Seasonic was ahead of the rest of the market in producing high quality, good efficiency PSUs with stable DC outputs wasn't clearly visible in the beginning, and few people actually knew enough about power supplies to look for those attributes.

Seasonic has traveled a long and winding road since then, and their marketing department wasn't much help. Today, Seasonic remains a very odd company in many respects, and it is difficult to compare them with many of their competitors. The size of the market for Seasonic products doesn't seem to matter; the company seems unconcerned with expanding their production facilities to meet market demands. Instead, management focuses on things like the development of newer and better products, preferring quality to quantity. That doesn't mean Seasonic is small, however; they manufacture many high-end, well known brands like Antec, Corsair, and PC Power & Cooling to drop a few names.

Of course, being manufactured by Seasonic doesn't necessarily mean that all of the brands are equally good. The consumer needs to understand that the Seasonic customer will only get the quality they can afford -- or the quality they ask for as the case may be. For example, a certain company delivered cases with pre-installed Seasonic power supplies (branded with their own name), and many of these power supplies went up in flames after a short period of time. Huge RMAs resulted from this, naturally, proving that there's a distinct difference between a Lexus and a $5,000 "luxury car" manufactured at a Lexus plant. As usual, you get what you pay for, and by refusing to pay for Seasonic quality the client received an inferior PSU. We're not here to talk about Seasonic's strategies and past business behavior, however, but rather we are here today to take a look at the new Seasonic S12II series, their latest product for the retail market.

The S12II series comes in four different wattages: 330, 380, 430 and 500. With these lower wattage power supplies, Seasonic is catering to the market where they built their reputation: silent computing. Expectations for their latest design will be high, given how popular the previous S12 and M12 series have been, both of which were huge successes for the company. The S12II features and new PCB design, though of course Seasonic seldom develops a completely new PCB layout. In most cases companies will take an older design and enhance it. (Seasonic's new X900 for example is based on a 2-year old PCB design.) This isn't necessarily a bad thing, especially if the original design is good, and Seasonic has a reputation for delivering some of the best quality power supplies on the market. That's a big compliment for any company, so let's see if Seasonic is worthy of such praise.

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  • Zds - Wednesday, September 19, 2007 - link

    Good review on a good product.

    What seemed a bit misleading, tho, was the statement about suitability of these models to dual-gpu machines. I know many marketing guys favor the "bigger is better", but it would not hurt to you, too, clearing out that the 330W model is powerful enough for practically any single-socket-single-GPU machine, and most of the dual-GPU ones, too and the 500W should be enough for almost any single-CPU-dual-GPU machine..

    And as most of the modern machines (C2D/Athlon, not P4) spend most of their time at idle, and most of them idle at 60-100W, the 330W model saves not just your ears, but real money, as you can run the machine at the sweet spot almost all of the time.
  • gochichi - Sunday, September 16, 2007 - link

    I have to say that Seasonic is not a flashy brand, like Antec or something. It's more of a truly better product, it doesn't rely on its name I don't think. Do a lot of people really know this name?

    From my experience, Antec is just plain average quality with a lot of marketing dollars ... and while I would buy Antec again, I wouldn't choose it over most other brands. In fact, I'd generally avoid it, as 2 Antec PSs burned out on me and 0 of any other brand, even duck brand ones haven't failed on me.

    My Seasonic 330W is going strong for 2 years now and my system isn't exactly barebones although this power supply kept me away from the vulgar video card options.

    While I'm tempted by the performance features of 8800's and 2900s, it's the elegance of power efficiency and silence that does the trick for me. After going through the very beginning of 3D acceleration, with the original Voodoo, I can attest to the fact that power hungry cards are best regarded as beta versions, as prototypes, as overclocked. As research and development, and priced for zealots.

    In any case, I understand going with more wattage on the powersupply, I would do so myself (mostly, b/c I like having different operating systems in different hard drives). But Seasonic is quiet, classy, quality stuff that deserves my recommendation.

    I would go as far as to call it an underdog brand, it's not Corsair, it's little mentioned in recommendations... but it's really good stuff. Seasonic is like delicious wine, in a world dominated by beer.
  • wibeasley - Saturday, September 15, 2007 - link

    The 330 version has been at newegg for at least a month. The "II" designation of the series isn't obvious from the title, but the box image shows it. The specifications show it as well, under the "Series" value.">
  • bryanW1995 - Friday, September 14, 2007 - link

    I'll take the 620 hx that I just paid 127 AR at mwave instead of 115 for the 550vx. Reply
  • USAF1 - Friday, September 14, 2007 - link

    I'm still waiting to see a review of a Seasonic S12 Energy+ PSU. Seasonic claims a peak efficiency of 88%. Reply
  • Christoph Katzer - Friday, September 14, 2007 - link

    Between that one and now are still around 20 other PSUs which are laying around here and want to be reviewed... Reply
  • tynopik - Friday, September 14, 2007 - link

    several of the charts such as efficiency, PFC and noise should be done on a watts scale instead of a % load scale. This will enable a direct comparison between alternatives.

    If i have a 250W load, how does the efficiency and noise compare among the 300, 400 and 550W power supplies? It's impossible to tell currently
  • Christoph Katzer - Friday, September 14, 2007 - link

    For what are the tables of page 6 then? Reply
  • tynopik - Friday, September 14, 2007 - link

    well yes i can figure out 50% load on a 500w PS is about 250w

    so yes it is 'possible' to compare numbers between different reviews, but certainly not easy

    and why use % load any ways? how is it relevant?

    convenience wise it sure would be handy to make, for instance, a single efficiency chart and a single noise chart with all power supplies that have been tested so far so you could see how they compare across the range of interest
  • Christoph Katzer - Friday, September 14, 2007 - link

    Sounds good with the comparison, have thought about it already for an upcoming price guide. Reply

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