Comparison: Efficiency and Acoustics



The efficiency chart shows good results for all the contenders. Since all the power supplies in this roundup have the same wattage, we can easily compare the results. Seasonic and be quiet! stick out from the group, both with efficiency higher than 85%. However, we can also see that these power supplies should run at more than 100W in order to achieve maximum efficiency. Antec also does well with over 84% efficiency from 150W to 500W.



The acoustic comparison doesn't show any major differences between the power supplies at lower output levels - levels that most systems will use. Hiper and Seasonic seem to have a similar fan control unit and fan as the noise levels are almost identical; likewise the Antec, Thermaltake, and Xigmatek units are all very close together. All of the units are near-silent up to ~300W, beyond which we see many scale rapidly in fan speed and noise levels.

The Seasonic and Hiper are the two best units up to 500W, as they stay under 20dB(A) throughout the range. Probably more impressive, however, is the be quiet! unit, which reaches a maximum 21dB(A) even at the full 650W output. be quiet! is famous in Germany for their low noise power supplies, and deservedly so. However, there's a tradeoff taking place: the lower noise levels are accompanied by higher temperatures, and running for prolonged periods of time at maximum load could cause problems. Then again, that's what the warranty is for, right? The be quiet! Dark Power PRO is not audible under most loads, which our graphic clearly shows. A constant noise level of 19 to 21dB(A) is definitely the best result we have seen so far. The other power supplies reach noise levels of up to 30dB(A), and while that may be noisier than some would like the lower temperatures are certainly not a bad thing.

Comparison: DC Output Stability Prices and Final Thoughts
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  • larson0699 - Monday, August 4, 2008 - link

    You mentioned that the label on the Thermaltake unit doesn't state maximum combined load of the lower-volt rails.

    But look, it does. 180 Watts.
  • BRDiger - Tuesday, July 29, 2008 - link

    I kind a wondering because comparing the efficiency level of the Be Quiet! to the testing datasheet on the 80plus.org site it just reaches about 80% at 100% load unlike your results with nearly 84%. Comparing it to the Enermax Modu 82+ review here, it even exeeds its efficiency
    Just wondering and it´s not supposed to be an offence...
  • BRDiger - Tuesday, July 29, 2008 - link

    Well, after reading another review it seems that 80plus was actually wrong and the be quiet!s performance exeeds the enermax..
  • strikeback03 - Friday, February 22, 2008 - link

    Thermal and fluids was not my best subject in school, but don't fans usually lose air off the tips of the blades, not suck it in? That is my experience with the Zerotherm Nirvana, which seems to make the same claim of sucking air in with its open fan.
  • mo3 - Friday, February 22, 2008 - link

    The new Enermax Modular 82+ & Pro 82+ can peak over 700Watts with out a problem; also they have the ATX12v V2.3 and reaching 88% efficiency.
    Modular 82+ has 2x 12 pin connection embedded for up and coming graphics cards and greater stability.

    Just to give the readers a better alternative! :)

    Check out more info at: www.enermax.co.uk
  • crimson117 - Friday, February 22, 2008 - link

    Okay... PSU review.. new 9600 GT review... I think anandtech is trying to tell me I need a new computer!
  • NINaudio - Thursday, February 21, 2008 - link

    Hi, you mention that the be quiet! PSU is quiet but also runs warmer than the others. Where are the temperature charts that we've seen in previous PSU reviews? It would be good to see the temperatures that you sacrifice for a quieter PSU. Is it a degree, 5 degrees, ten degrees, more?
  • tynopik - Thursday, February 21, 2008 - link

    1. include a real stress test like how the units handle rapidly changing input voltage

    say load them up to 80% capacity and then connect them to a variac and dip the voltage to ~90V 3 times in quick succession to simulate a brownout or poor electrical conditions and check that
    a) it doesn't blow up
    b) it maintains quality output while the input if fluctuating

    2. include cheapo units for comparision just for the reminder of what a poor quality unit is

    3. i really love your connector length charts, far more useful than the usual 'stetch a jumble of cables out and lay a ruler next to it' approach. i just wish you would do the same for the sata/peripheral connectors

    4. i'm really like the way you combined all the acoustic and efficiency charts together instead of having a bunch of individual charts
  • Christoph Katzer - Thursday, February 21, 2008 - link

    I just assembled a nice system do to those tests. Once it's up and running I will include it. Will also make a comparison of all cables from now on, thanks.

    The problem with cheap units is that they are mostly for a specific market. I would need to buy thise units myself since no company would ever send them over. Since I am not in the US I will only have the stuff from Europe which is not even available in the US. But let us see how we could change that in the future...
  • jtleon - Thursday, February 21, 2008 - link

    Chris,

    You state that at least 100W must be drawn before these units achieve high efficiency. Can you relate this requirement to most normal PC tasks - i.e. browsing the web (reading Anandtech reports of course), answering email, other office based activities (the majority of PC users on the planet), rather than those hardcore gamers that are gaming around the clock (and clearly are independently wealthy!).

    It would appear that these PSU's are not going to efficiently reduce the carbon footprint of the majority of PC users on this planet.

    Am I wrong?

    Regards,
    jtleon

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