Test Setup DC Outputs

As usual we are testing with our Chroma programmable loads to fully load each rail to a specific amount. This is important to get truly accurate results and not merely approximate values. The tests are conducted in two different temperature environments. One is normal room temperature of 25-26°C, while the second environment goes from room temperature and increases steadily up to 50°C. Especially during the higher temperatures we will see how good the power supplies are and what they're really made of. Components inside will perform much worse at higher temperatures, but we expect any good quality PSU to deal with such test conditions without failing.

Note: If you would like to know more about our testing methodology, equipment, and environment, please read our PSU Testing Overview.

330W Rail Loading
PSU Load 3.3V 5V 12V1 12V2 Wattage
All Rails
10% 1.06 1.18 0.94 0.94 33
30% 3.19 3.54 2.83 2.83 99
50% 5.32 5.91 4.71 4.71 164
80% 8.51 9.45 7.53 7.53 260
100% 10.63 11.82 9.42 9.42 324

500W Rail Loading
PSU Load 3.3V 5V 12V1 12V2 Wattage
All Rails
10% 1.42 1.42 1.54 1.54 50
30% 4.27 4.27 4.63 4.63 150
50% 7.11 7.11 7.72 7.72 249
80% 11.38 11.38 12.35 12.35 392
100% 14.23 14.23 15.44 15.44 487

To provide a better overview about the different temperatures and input voltages we test, we have decided to combine the input voltages into one graph and not four separate charts. We show an area in which the voltages have been measured. In past reviews we have seen steady voltage drops with increasing loads, and this new style of graph should make the results clearer. Each graph will show a single line and the distributed measured voltage fell inside of the specified area during testing.


330W


500W


330W


500W

Seasonic lives up to their promise of very tight voltage regulation. The voltages don't drop much from the optimal amount and hold pretty much stable under any condition we could have come up with. The 500W version doesn't seem to perform quite as well, however.

The Inside, Cont'd DC Outputs, Cont'd
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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.

    http://www.newegg.com/Product/Product.asp?item=N82...">http://www.newegg.com/Product/Product.asp?item=N82...
  • 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.
  • 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%.
  • 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...
  • 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?
  • 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.

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