How to silence a computer

We won’t go into this in-depth or cover all the products you can use here; that’ll be for a feature and reviews at a later date, but in short there are a number principles you can follow to reduce the noise your PC makes based on an understanding of the nature of sound waves and how they propagate.

First and foremost, the golden rule: it is better to stop a noise at the source than trying to silence it after. In other words, start by looking at which noises you can reduce at the source (slower spinning fans, for example) or eliminate completely. Core options here include GPUs and hard drives (more on this below), but can also include the CPU if you use a very low-power chip (something you might consider for an HTPC, for example). Mainly, don’t use a boatload of fans inside the case just because you can – keep them to a minimum without compromising your airflow through the case, which may require good layout for your components and cables within the chasis, or buying a case with good airflow; more and more cases these days are being designed with this in mind.

But if you can’t prevent the noise in the first place, your only avenue is to try and reduce it. Here are some tips for each subsystem:


CPUs
The faster a fan spins, the more noise it makes. Larger fans can spin slower than smaller fans but push the same amount of air. Therefore it’s a good idea to use as large a fan as possible where you can when it comes to cooling – especially for an area where you expect it’s going to spin up to full power under load, like on the CPU. So, unless you really need a compact heatsink and fan solution, always buy a CPU heatsink that takes a 120mm fan, or larger if you can get it.

GPUs
There’s no free lunch so don’t expect to be able to get a high-end card, overclock it, and run it under load and not be making a noise. If you want to remove this source of noise, get a passive heatsink-cooled card, but be aware this means it won’t deliver top of the range power and it probably won’t be clocked high. That’s the trade-off. Easily viable for HTPC setups, however.



PSUs
Ostensibly there have been over the years a number of ‘silent’ PSUs that usually forgo the fans for whopping great big passive heatsinks. They do work, but come with some caveats: firstly unless the heatsinks extend outside the case, you’ll still need airflow cooling inside, which means you still need fans somewhere nearby (possibly negating the whole point of removing the fans from the PSU in the first place). Secondly, since the PSU’s heat comes directly from providing power for your box, the more juice it gives the hotter it’s going to get. Usually, this means ‘silent’ PSUs are limited to low wattages (400W or less) and may not be enough to power your beast. In this case, stick with high-powered PSUs, but follow the advice above for CPUs and choose one that uses a 120mm fan and not one or two 80mm fans.



Hard drives
Use drives known to be quiet, like some of the Samsung range and recent Seagate drives. Alternatively, try drives designed to be quiet like Western Digital’s new ‘green’ drive, which is quieter by virtue of its methods for saving power – but which again can come at a performance cost. Pretty soon now SSDs are going to become standard, and these are the first mainstream storage devices for PCs that are literally completely silent – no spinning platters, no actuator heads. Silence is golden, or at least silicon. If you can’t wait until then, you can buy SSDs now in sizes from 16GB to 64GB, but they come at a pretty penny.

Grommets
Rubber and silicone grommets are a mainstay of quiet computing; these absorb vibrations and thus, in turn, reduce resonance. A good case designed with silence in mind will come with rubber grommets for hard drives and sometimes fans as well. Alternatively, grommets for fans are easy to find as fans have a ubiquitous attachment for cases. Hard drives can depend on the hard drive enclosure for the case, but usually you can find grommets to fit. Ideally, every hard drive and every fan needs to be attached with grommets to minimise resonance. If you’re crazy, you can do the same for the PSU and even GPU cards (remembering their high powered fans), using silicone separators to screw them to the chassis backplane.

Cases
There’s two types of cases you can look at: those with good airflow, which can direct cool air where it’s needed most or help to minimise the need for fans; and cases that are designed to be one gigantic passive heatsink. The former you’ll find in varying degrees from quite a few case manufacturers. Shop around, and look carefully at the inside shots of a case on websites for the models you’re interested in. Analyse where you’ll put components, and how the air is going to flow through. For the latter there are cases like Zalman’s TNN, which is quite literally one gigantic passive heatsink with internal heatpipes to directly connect components to the heatsink-case. These cases are probably quite effective, not to mention supremely heavy, but come with the caveats that they are usually very expensive and a pain in the bum to setup (for example, removing a GPU’s fan and heatsink assembly in order to connect it to the case heatpipes). Then again, if you have the money to buy one of these you can probably employ someone to build it for you too.



Insulation
AKA sound proofing. There is an entire industry devoted to silent computing and key to it is the range of sound dampening materials you can buy to line a chassis. This is the last bastion of defence against noise – when you’ve done all you can do and various components are still producing noise, however small, those sounds are travelling from inside the case to the outside; unless you stop them before they can. Sound dampening materials usually consist of foam and rubber – unstructured substances whose molecules don’t conduct sound waves well – and can be attached as lining to the inside of a case (top, bottom, side panels, and even drive bays). Generally these products do work, but don’t expect miracles. It’s unlikely they’ll ‘silence’ a sound, but they can muffle it and reduce it so that you don’t notice it so much. As usual, there are some caveats: firstly, more effective materials will generally take up more area – more mass – but you don’t always have a lot of area free inside a case, especially on the side panels. Secondly, because they literally insulate bare metal edges of a case, hot air inside is less likely to be cooled through heat conduction and convection (see X-Ray ‘The Cold Universe’, Atomic issue 74) to the outside, and so ironically sound dampening materials can raise the inside temperature of a case – which might result in fans spinning faster to expel hot air. No free brunch, either, eh?



Baffles
Baffled by baffles? Ironically, even a good sound-proofed case usually leaves one side untouched: the rear. It’s impossible to line the inside rear of the case as it’s usually flush with fans and external connections for the motherboard and plug-in cards. Especially with exhaust fans, their noise goes right out the back and bounces off the nearest wall on its way to your ears. The solution is to use a baffle, but these are extremely hard to get – Silverstone used to sell one (the SST-PP02) for PSUs, but this doesn’t prevent sound from external fans as well. Plus, the problem with baffles is that by design they create an external enclosure outside the case which can, sometimes, inhibit airflow out – somewhat defeating the purpose of the fans and possibly causing them to spin faster and produce more noise as more heat is expelled. However, we’re sure a good design is possible – perhaps we’ll get Ron onto the case (pun)!


There’s plenty you can do to help save your ears from PC noise, it just takes a little careful planning, sometimes hand-picked products, and of course a better understanding about the nature of sound.