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Silent Running: Two Fanless Power Supplies And A Quiet One, Tested

Two Fanless Power Supplies, Compared

Given the number of massive CPU coolers and loud graphics cards that make their way through our lab, it's easy to overlook the noise coming from power supplies. In general, power supply fans are drowned out by other system components. Even a mechanical hard drive tends to be more noticeable than a nice, big 120 mm cooler lackadaisically blowing air through large vents in a PSU.

But just ask anyone who's been burnt by a cheap power supply, or someone who hasn't blown out their chassis in a couple of years: PSU fans can get really loud.

What if you simply want a super-quiet machine? A computer for the living room or bedroom, perhaps. There are such things as passively-cooled graphics cards. Even more effective, liquid cooling has the potential to draw heat away from your components and dissipate it using larger, slower-spinning fans that generate barely a whisper. Swap out that clacking hard drive for an SSD and really, there's not much left inside your PC to disrupt the glorious silence.

Well, almost. There's still the issue of that ever-turning power supply fan.

Today's energy-efficient power supplies waste less power as heat than they used to. However, they still require cooling. And of course, the easiest way to achieve that is with a fan. But there are passively-cooled power supplies without fans (and other models specifically equipped with low-noise fans) for applications that demand silence.

We grabbed three PSUs purportedly known for their acoustic qualities, hoping to find at least one worth recommending. Upon hearing our call for submissions, Seasonic and SilverStone each sent in a fanless model to test. The former gave us a look at its X-460, while the latter shipped off its SST-ST50NF. For the purposes of comparison, we grabbed a single fan-cooled unit that's supposed to be ultra quiet: be quiet!'s Straight Power E9 CM 480 W. Unfortunately, you can't get it in the U.S., so it's really serving as a point of reference here today.

It's also notable that none of these are designed to sustain more than 500 W of output. Higher-wattage power supplies generate more heat under load, even if they're very efficient. As a result, passive cooling generally isn't an option once you start looking at more enthusiast-oriented configurations.