If you want a power supply that makes as little noise as possible, you can purchase a passive power supply. Without a fan they should be a lot quieter than conventional power supplies. In this review we take a look at six completely fanless models between 230 and 550 watt. We also compare them with two proven non-passive models.
In the past power supplies made quite a bit of noise, even at lower load. At the moment this is different, at least with somewhat decent models. For the last years there has been a race to get as high an efficiency as possible, which has another added advantage: less generated heat. Because of this, power supplies can even be designed semi-passive, with a fan that only starts turning at higher load. These are found more and more on the market. Because of this a lot of power supplies are inaudibly quiet or even completely quiet at low load in practice, which is becoming more and more the norm.
However, there are also completely passive power supplies – without fan – that are also supposed to be completely silent. When absolute silence is needed, for example in a studio-environment, these theoretically have the preference, because they will never produce fan-noise. Passive power supplies also have disadvantages. Electronics have a higher durability when they do not become too warm, and without active airstream the parts of passive power supplies have to endure more by definition, which means they could break down sooner. That said, we do not have any evidence to back this up. In order to ensure the longevity, a passive power supply needs parts that are as robust and efficient as possible and therefore more expensive parts, which can be seen in their price. This is also not lowered by the low competition in this niche segment.
That high price raises the question whether or not passive power supplies have an added advantage in practice when compared with a good active or semi-passive power supply, with a fan that can produce airflow when needed. Therefore, we do not only take a look at six passive power supplies but also compare them to two non-passive models.