Quiet/fanless computer

Question

I want to buy a computer which is quiet, i.e. I can leave it in my bedroom without noticing it (under normal load; I might rarely do some heavy processing, where I can accept that I would hear the fan, or on lots of HDD access, it's ok if I quietly hear the HDD; mostly very similar to my MacBook). Also, it should not consume too much energy (because it should run permanently; again similar as my MacBook). It should come in a tower where it is easy to install further disks or other hardware (unlike my MacBook). It also should have wifi.

Initially, this will mostly be a fileserver, running Linux. Maybe additionally some software like Perkeep, which needs lots of RAM (10GB or so) as far as I know. But maybe I want to run some other stuff (some scripts, maybe home automation stuff) later on it as well.

I was looking a bit around. But already for the power supply, I did not found much without an active cooler. Maybe water cooling? But as far as I know, this also has some active cooling element? I would prefer a solution which only comes with passive cooling, if something like this exists.

(Related question is here, but I don't really want a mini PC (or at least not necessarily). Preferably I also want to buy the individual components separately and configure it how I like it, at least if that is cheaper.)

Answer 1

The more powerfull (TDP (thermal dissipation power) in watt) the computer, the more you need to cool it down. You can combine one or several of these:

• You can pick low energy components (CPUs). You can further underclock the CPU or undervolt it so it consumes less energy, hence heats less. Usually when the technology makes a new step (transistor size reduction, manufacturing optimization), the efficiency increases.
• You increase the radiator surface and lower the fans speed. For instance, your can take a big CPU cooler such as the Dark Rock pro 4, or use multiple watercooling radiators (which can be large: 360 , 480, and thick: 6cm for the EKWB XE).
• In the case of water cooling, pick an efficient radiator and designed for low speed air flow. Hardwarelabs has a full spectrum of radiators optimized for different airflow speeds; pick one for low speed. Extremerigs does many reviews and can help you to pick those you're looking for.
• You can pick a case that is designed to absorb sound frequencies, such as Fractal Design cases (the Define series).
• You can use a silent profile in the BIOS in order to drive quietly all the fans.
• Then you can put the PC in a distant place (eg. under the desk). Just remember that the noise energy decrease in a law of d^-3 (where d is distance) in an open space, d^-2 if it's between 2 boards/walls, d^-1 if it's in a tube. Hence space design, placement and room matters too.

Answer 2

The majority of PC noise is cooling related...

1. The less heat you generate, the less noise generated
2. Conversely, you can cool it less, making it run hotter, albeit if you go too far, you can reduce the lifespan of some components
3. Or you can cool better; expel heat more efficiently, so less effort required and less noise produced
4. Or you can directly try to tackle/block the noise

In addition to Soleil's good suggestions...

• If your BIOS does not have a silent/quite profiles or PWM fans, you can use inline resistors between mobo and fan cable to reduce voltage to 7v, which in turn will reduce speed and thus noise. (Approach #2)
• You can add insulating materials to the case, usually foam or fibre pads that absorb/dissipate some noise. (#4)
• You can buy a larger case, or de-clutter the inside of the case (e.g. careful, neat cable routing) to reduce airflow obstructions. (#3)
• On similar lines, a common airflow approach is a low, front-facing intake fan to an upper rear exhaust fan. Whatever your approach, try to encourage a single airflow route from a cool intake fan, across all key components, to that upper exhaust fan. (#3)
• Consider having more/larger fans but have them running slower (i.e. via resistors, above) - more airflow overall (#3)
• Get a case with the PSU in a sealed compartment at the bottom of the case. Old-school cases used the PSU at the top as an exhaust fan of sort, so hot case air would enter the PSU, where it is heated further, and heavily loads the smaller, lower flow PSU fan - avoid this.
• Use a premium, aftermarket thermal paste, rather that the standard stuff that comes with your cooler, and make sure you apply it correctly (#3)
• For mechanical noise, an easy win is to buy silicon grommets and/or plastic screws to reduce the noise from HDD vibration passing through to the case. (#4)
• Also you can buy rubber/silicon gaskets to place between fans and the case to acheive the same ends. (#4)