When a power supply becomes sufficiently efficient, it loses less energy from the input as heat.  Given the right conditions, a very efficient and low rated power supply can be built without a fan, giving a quieter experience.  The limit is always a balancing act between efficiency and seeing how highly rated the PSU can be – there is a certain segment of the market that will always prefer the quiet systems where possible.  Up until this point, the peak rating I have used for a fanless PSU was 500W, from the Rosewill Silentnight range that were 80 PLUS Platinum rated.  Even though Titanium rating has become a thing which might help push the limits even further in the interim, more fanless Platinum models are coming to market. SilverStone showcased a 520W Nightjar model and Enermax showed off a prototype 550W digital fanless version.

SilverStone 520W Nightjar

Despite the word ‘night’, this all-white PSU will come in 400W and 520W variants and will be fully modular.  It seems like it will have at least four PCIe 6-pin connectors, and I assume some or all of which will also be 6+2. 

Due to the fanless design, it must be oriented in a specific way to maximise the airflow.  All the power is on a single 12V rail, with the unit rated up to 516W and 43A, which should satisfy all single GPU devices out in the market at stock speeds.

I might have to take issue with the ‘zero dB’ claim, given that electrical noise is around 15 dB.  In the past I have also seen silent power supplies with significant bulk to help radiate temperature away, whereas this unit seems fairly empty.

From previous experience 500W fanless Platinum power supplies are not entirely cheap, and the Nightjar has recently gone on sale for $160.

Enermax 550W Digifanless

Digital-monitoring power supplies have had a rough entry into the market.  They add a good amount of cost to a unit, but few users interact with their power supply on such a scale to monitor and adjust the unit for best efficiency and performance.  With all that being said, I have not yet come across a fanless digital-monitoring power supply, and Enermax believes there is a market for one.

Unfortunately they did not have an individual unit on show that was not in use, but the design is fully modular and the system is rated at 550W.  I did ask about the rating, and it turns out that 550W is a peak value, whereas the average value is more around 500W.  Perhaps I am naïve in power supply marketing, but I had assumed that the wattage listed was the average due to issues in the previous decade.

At this point I believe the Digifanless is still in the prototype stage and will be coming to various markets later in the year.

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  • thekimbobjones - Thursday, June 12, 2014 - link

    Disappointing to see Enermax has rated this PSU as 550W when it is really a 500W. Dangerous territory.
  • mczak - Friday, June 13, 2014 - link

    My guess is that from all the components this is really designed to handle 550W easily. However cooling (or rather lack thereof...) means it can't sustain this for a long time without overheating. Such behavior is quite common for fanless psus, though I agree it shouldn't be advertized as 550W (though I guess it might be possible it really is 550W if the airflow in your case is done in such a way that it moves some air through the psu too). In any case, imho there's not all that much value in high wattage fanless psus (you're not going to cool the rest of your system passively if you're burning more than 500W...).
  • SleepyFE - Friday, June 13, 2014 - link

    I agree that you GPU will probably not be passively cooled and for now no CPU is, but every little bit helps. If you can make one part fanless the overall noise will be lower. At the moment that part is a 500W PSU (more then enough power). When they decide that the CPU is powerful enough they will start making passive coolers for that...
    At some point you will be able to build a powerful fanless system. The PSU is the first stepping stone, so i say kudos.
  • thewhat - Friday, June 13, 2014 - link

    "I might have to take issue with the ‘zero dB’ claim, given that electrical noise is around 15 dB."

    Doesn't this noise vary across configurations? Or is this a known spec of the PSU?
    I've seen reports on PSUs ranging from "complete silence" to "clearly audible electrical buzzing".
    I have a fanless Seasonic and the not-audible-from-my-sitting-position buzzing varies also depending on which components are attached to it.
  • Acarney - Friday, June 13, 2014 - link

    I'm wondering about that too. Is the electric noise only ~15dB when fully loaded at ~500w? Or would it be there when just at the desktop and idle (or like 20% or less CPU usage with a haswell i7?). I know I wouldn't need 500w, but I figure going larger on the PSU would be better (it would stay well within temp limits since it is t always loaded) and some room to play with upgrades in the future.

    Honestly though, 15dB at six feet or so (say for a HTPC) isn't really noticeable probably, especially if it's even less when idle or in standby during nights...
  • Ian Cutress - Friday, June 13, 2014 - link

    30 dB is a leaf rustling, and every 3 dB is 2x volume as it is a logarithmic scale. So 30 dB to 15 dB is 2^5 times differece, or 32x quieter. So you probably won't hear it, but from a physics standpoint it is erroneous.
  • ShieTar - Friday, June 13, 2014 - link

    But are you sure you can tell the difference between 15dB and 0dB with the required accuracy? I seem to recall that most noise measurements posted on AT use 30dB as a lowest reliable result. So really, what is the accuracy of your 15dB result?
  • DanNeely - Friday, June 13, 2014 - link

    It's 32 times the energy; but that's not the same as saying it sounds 32 times louder. Your ears (and eyes) work on log scales too; and a 10db difference is only perceived as an ~2x difference in how loud the sound is.
  • jeffrey - Friday, June 13, 2014 - link

    What happened to the Rosewill SilentNight 500W? It has a pretty much perfect 5 star set of reviews on Newegg, but has been not available for a while now. Haven't seen a replacement model..

  • 'nar - Friday, June 13, 2014 - link

    Also be aware that it is the PSU that isolates the system from the noise of the power grid. If there is an air conditioner or refrigerator out of phase you can get electrical noise from that broadcast out to any device on that side of the fusebox. So you have to consider the electrical source when evaluating PSU devices, and that is not often listed in reviews.

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