Efficiency Comparison

The problem most users do not realize today is that if you have lower wattage units you cannot really have the latest technologies inside since it just doesn't make sense. Fancy components and features costs money -- it doesn't matter if they are in an 800W or 300W unit. If you make a small power supply with very high quality features, the user will need to pay for it. The unfortunate truth is that there would be nobody out there willing to pay $150 for a 300W power supply because there are tons of options with prices starting as low as $20. The important thing is to know why you want to have a better quality product, which for most people today is the higher efficiency these units can deliver. If you have a price difference of $50 from your product of choice to a higher efficiency power supply with similar specs, then it will most probably not make any sense since you will need to run the power supply for several years 24/7 to overcome the initial investment.

We discussed this in our article about power consumption and why it is so important to know more about your PC and its components. With today's products we see 82% as a mark every high-end product should be able to reach, which is why we start from 82% with a green graph. Everything below will be red just to show you the efficiency wasn't that good. Don't be worried about the first graph of each power supply since that represents 10% load and no power supply that went through our hands was ever able to come even close to 80% with such a low load. This is why 80 Plus certification for example starts at 20% load. The second graph represents 20% load, the third 50% and the last represents full load. Here again, the more green bars a power supply has the more efficient it is. All of the efficiency results shown are with 230VAC for ease of comparison; efficiency will be slightly lower on 120VAC.

Since the manufacturers are primarily focusing on higher wattage power supplies with new technologies that bring better efficiency, we didn't expect any miracles today. However, some units again stand out from the crowd. Many of the power supplies reach 85% efficiency, which is a very good development. Power supplies from Enermax, OCZ, PC Power & Cooling, Silverstone, and Thermaltake show very good results. The Silverstone Element tops out at incredible 89% efficiency, which puts it at the top of the group a second time.

The following graphic shows the efficiencies below 80% which wasn't possible to include before. Please note the efficiency at 10% load of the FSP OEM unit is with only 61% not visible.

Acoustic Noise Comparison Cable Length - ATX Connectors


View All Comments

  • Christoph Katzer - Wednesday, December 31, 2008 - link

    We cannot run after every brand there is and if those companies don't come to us... there are surely many more missing but we can only test products from companies that are actually interested in us testing their stuff. We had an Akasa unit before though... Reply
  • boboko - Sunday, January 4, 2009 - link

    >"We cannot run after every brand there is and if those companies don't come to us..."

    I guess that is the problem with almost all review sites. And the worst thing is not that you skip the smaller guys, but that what you are reviewing is not off the shelf, it's sent to you buy a company that wants a good review. So even if they have rotten quality control, and half their stuff is DOA, you know the one they send you has been triple checked and fine tuned. Not your fault, but to me the reliability is MUCH more important than a few extra watts or a few less decibels, and there's just no way to get good data on that.
  • Griswold - Wednesday, January 7, 2009 - link

    If you read the reviews here, you'd know that this assumption is false in general. AT has had junk on their bench on more than one occassion - if every supplier would do what you claim, all reviews would take place in happy bunny land where everything is dandy and no negative notion is possible. But thats not the case.

    Surely there will be those who go the extra mile to make their product look better than it is off the shelf, but you just cant hide every trace of incompetence and bad quality.

    Much like we cant expect a review site buy every piece of hardware to test it and hope they can re-sell it without a loss.
  • marc1000 - Thursday, January 1, 2009 - link

    wow, I know it was said before, but you guys really do listen to us. that's the reason I come here everyday to know the news! keep up the good job at 2009! regards! Reply
  • C'DaleRider - Wednesday, December 31, 2008 - link

    I'm just curious why the "old" version of the Antec Earthwatts 430 was dug out and retested since Seasonic is no longer the OEM for it but now has Delta as the OEM supplier and has been for many months now.

    Seems it'd be only fitting that the "new" version would be tested instead of a version no longer being made or sold, except as NOS (new old stock).
  • Christoph Katzer - Wednesday, December 31, 2008 - link

    If only "someone" could send it to us :] I will make sure to get new revision on time, you're totally right. Reply
  • sprockkets - Wednesday, December 31, 2008 - link

    What were those bad things happening to the SII Seasonic PS? Reply
  • JarredWalton - Wednesday, December 31, 2008 - link

    I believe Christoph is just saying that he's received an increase number of email messages from people saying that their Seasonic PSUs have failed. It's anecdotal at best, and it could just be a case of more people buying their PSUs and thus a small fraction that fails can still result in more complaints than before. Reply
  • Christoph Katzer - Wednesday, December 31, 2008 - link

    Yes ;)
    There was a revision in the beginning that had problems with certain motherboards somehow, something to do with the "power good" signal. They've upgraded the series long time ago though.
  • Lonyo - Wednesday, December 31, 2008 - link

    I'd just ordered some new parts, including a CX400 about 30 minutes before I saw this article come up.
    Nice to see that my choice seems fairly solid.

    I'm sure this article will be relevant for other people as well.

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