Power Supply Roundup: 650W-680W

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.