The Silent PC
Site last modified May 2, 2023

The Silent PC web site investigates the acoustic aspect of information technology (IT) ergonomics, and a growing market for acoustic comfort. Its most important conclusions:

The target audience of the site comprises purchasers and purchasing managers prepared to pay for sound quality engineering and low levels of unwanted sound - and industry decision makers.

We have recent years seen an enormous increase of interest in noiseless computers, and other kinds of low-noise information technology equipment. Where there used to be very little to find when searching the Internet for these subjects, can we at this point find hundreds of thousands of references. Most computer magazines and web based IT hardware reviewers now write on the unwanted sound issue. Levels of noise emissions are these days mostly included as an important parameter in IT hardware reviews.

Noiseless information technology has recent years also become business. Not only many system units, data projectors and printers are built and marketed as quiet, but a new market for silent and quiet computer parts has evolved. Many users are annoyed by their noisy machines, and seek solutions for to make them comfortable.

Today's intense market for tablets and smartphones also fits well with this trend towards noiseless computing.

Speech intelligibility and acoustic comfort are quietly - still rarely commented as a phenomenon per se by the World's business press - becomming substantial product and service differentiators: The IT, automotive, air-conditioning, heavy equipment, building, hotel, home appliance, high-speed train and aircraft industries are just a few examples of business fields that nowadays invest a lot money to achieve low levels of unintentional sound, in sound quality engineering, and optimal conditions for speech communication.

There is, however, something that still limits the use of these rather new differentiators and their opportunity for business, not only for IT equipment, but for most product groups and services where it isn't possible to base a choice on their acoustic aspects before buying: The relative notions "quiet", "almost silent" and "high acoustic specification" now inreasingly common used in advertisements, have by most manufacturers and sellers not yet been paired with comparable figures on which to make buying decisions, and most purchasers haven't been informed on how to use these now rare values. For the present acoustic comfort and speech intelligibility therefore remains an exlusive market where only the most technically interested reading reviews and a few well-informed purchasing managers knowing what standards to ask for, will find out what products and services are worth buying.

This first page provides an background and introduction to the IT noise issue, the new market for noiseless IT equipment - and its current limitations. Lastly it tells some of what powerful manufacturers like Intel®, Microsoft®, Dell®, Hewlett-Packard®, Apple®, IBM®, Fujitsu Siemens Computers®, AMD®, VIA™, SAMSUNG and some other important companies and governments say and do about unwanted sound.

Even if not as often as in the 1990s, we still say that the industrialized part of the World now is in the era of the information society or knowledge society; also named the information age. Living and working in this era, superimposed on the industrial society era, we believe that information, knowledge and communication are in focus. The most prominent symbol for the information society era is our information technology. Like most of our machines does our information technology equipment still often unintentionally produce sound: Such sound has almost always constituted a side-effect of our wealth-creating technology, and such sound has been a prominent feature of the industrial society era.

On a psychological level has Man's relation to this unintentional side-effect since ancient time been dualistic: It can still either be regarded as something wanted, or unwanted. When wanted is the word we use for it sound, when unwanted do we name it noise. When thinking on sound as a positive side-effect of technology is it most often psychologically associated with power and masculinity, or wealth and security. Man's dualistic relation to machine and equipment sound, explains why both the acoustic aspects of ergonomics and comfort often have been neglected. In the information age this is about to change.

Today we not only know that high-intensity noise emissions can be dangerous to our hearing organ, but also that even low-intensity noise emissions often adversely affect our well-being, can degrade speech intelligibility, and may have adverse effects on both human performance and health. We are now also in possession of technology to measure unwanted sound, and knowledge on how to objectify and minimize it.

This rock-carving from Tanum, in the south of Sweden, was probably created about 3000 years ago: 2000 years before Norse Vikings landed North America. Experts have discussed what it shows. Some say it is a portrait of the god Thor; the most powerful of the Norse myth gods, and also known as the god of thunder, riding around middle-earth in his wagon drawn by two goats.  Others say that the man in a wagon may be a predecessor to Thor, like the Celtic god Taranis: The name Taranis derives from the Celtic (or Indo-European) root 'taran' meaning thunderer or thunder.

In conclusion, it isn't possible to be sure on what this historical work of art on a flat rock shows, but it has been associated with a god capable of causing mighty sounds.

The rock-carving in Sweden can, however, also be used for to compare from where we came to today's information society era: Rock-carving was an early kind of communication, and the stone and flat rock used for the carving can be seen as a primitive kind of information technology equipment. Rock-carving did for sure cause sound: It has been said that this side-effect even could have been part of a magic ritual. Today's information technology equipment still often as a side-effect cause sound, but few would say that there is anything magic involved.

Vitlycke World Heritage Museum is where you can see the rock-carving. Image courtesy of Bokförlaget Signum.

Possible adverse effects of continuous low-intensity sound, like the one that may emanate from PCs and other technology intended for use in offices and homes, are all based on the fact that audible sound consciously or unconsciously calls for and competes for attention, and that monotonous sound decrease alertness.

Alertness is a basic prerequisite for full attention. Attention, in turn, is what is utilized in information apprehension and information processing; thus a component of human brain function of utmost importance when utilizing information technology: Unwanted monotonous sound emissions (acoustic noise) both decrease the human brain's signal-to-noise ratio and alertness, and are therefore basically a counteraction to the very purpose of information technology. By interfering with the human brain's information processing system, acoustic noise emissions counteract the very purpose of information technology.

The power of silence lies in that it provides a neutral background towards which sounds of interest can be heard, and frees brain-energy for treatment of other kinds of information than acoustic. Total and continuous silence is of course as boring and sensory depriving as too much unwanted sound.

Like our computers can the human brain only process a limited amount of information per time unit: In Psychology and Neuroscience this construct is known as "working memory". Because of the human brain's limitations is it important to provide it with as valuable as possible information; when we want to use it as constructively as possible.

For to utilize it as efficiently as possible is it also important that the human brain doesn't have to work too monotonously, or stand too much monotonous information, and that it like the rest of our body is allowed to rest thoroughfully at regular intervals.

Unintentional IT equipment sound can in some way be regarded as information, but commonly we don't need this information: Commonly we don't need to continuously be informed that a piece of IT equipment is on, and how this sounds.

Personal computers are not the only kind of information technology equipment often emitting too much unwanted sound. Printers, copiers and fax machines are other examples, and nowhere else is the counteraction between noise and information technology more obvious as when high educated listeners to high educated speakers sometimes still have to face the, for members of an information society, degrading experience of having to try to focus on what the speaker says through the humming noise of an underdesigned projector.

Projectors, as well as all other kinds of IT equipment, can also be declared using the intelligent international standard for unwanted sound the information technology industry agreed upon in the 1980s [1].

When writing on the ergonomic benefits of quiet machines is it inevitable to also acknowledge speed as a most valuable aspect of IT ergonomics. In fact, speed and performance constitute the sole reasons why computers at all were invented: We wanted computers to help us doing things faster than we were able to by our own brains and hands. Slow IT equipment can cause as much distraction as noise emissions. Therefore, the faster our machines are made the better will also one of their ergonomic aspects become.

Man's imperfection, however, doesn't make it too easy to build high-performance and yet low-noise information technology equipment, but the fact that we face difficulties when trying to combine optimized acoustic and performance aspects of IT ergonomics, doesn't mean it isn't possible.

If the computer industry can agree on a coordinated approach to the power management and thermal issues of the now maturing information age technology, will it also become easier to improve its acoustic aspects; while maintaining the need for increased speed, performance and reliability. This subject is further discussed at the Intelligent PCs page.

In the information age peoples' concentration, but also optimal conditions for hearing and comprehension are of main importance. Acoustic engineers represent a group of professionals involved in improving these basic requirements for this new era: For to optimize sound perception and speech intelligibility they not only work to minimize background noise, but also strive to achieve optimal reverberation times in rooms, and design products' sounds so that they best suit humans and their intended contexts.

Acoustic science can be said to deal with how to aid humans in sorting out valuable acoustic information from less valuable, and sorting out unimportant sounds from more valuable kinds of information. Acoustic science thus is one of the sciences providing the fundament for the information society.

An until recently rather low demand for acoustic services, has led to that now only the most mature industrialized nations are in possession of qualifying acoustic facilities and expertise.

Sound is an often neglected aspect of freedom: What do we want to listen to? What sounds do we want to expose our ears and brains to?

Continuous exposure to unwanted machine and equipment sound has for a long time been left to experts to decide about: These experts have helped to find out what is an acceptable level of high-intensity acoustic noise emissions so as not to damage the organ of hearing, but they have also been trying to figure out what levels might be acceptable for low-intensity acoustic noise emissions, like the ones from machines and equipment intended for use in offices and homes.

The Silent PC Web site promotes an approach regarding low-intensity acoustic noise emissions probably better suited a modern society and the special properties of this kind of emissions: Purchasers' freedom of choice, and manufacturers' freedom of competition.

Freedom of choice requires that there are alternatives, and that there are means to compare: There are no "listening rooms" for information technology equipment, like for HiFi equipment, and IT purchasers can't like car purchasers take products for a "test-drive" before buying. There are now two alternatives for those interested in identifying low-noise IT products:

Today's purchasing departments and private persons buying PCs, printers, projectors and other kinds of information technology equipment, will still only on rare occasions be provided the objective information they need for to make buying decisions according to level of noise emissions. If at all, will still most buyers find themselves facing subjective statements like "our PC is almost noiseless", "our printers are as quiet as a whisper", "our projector is quieter than others", "our graphic card is most silent in the business", or "we have been able to bring down the noise level 50% compared to an ordinary hard disk".

These subjective statements based on relative notions are of course of little value if not paired with objective figures obtained in a standardized way.

The few manufacturers that use exact figures to declare their products' noise emissions, except of the powerful ones now adhering to international standardization, most often either forget to obtain and declare them according to their international standards, or forget to state that they are using these standards: Thus the rare use of decibel - dB, dB (A) or dBA - figures, with few exceptions, still misleads customers to believe they are able to compare products' noise emissions, but dB, dB (A) and dBA don't mean anything if it isn't stated according to which standards their values have been obtained. What make things even worse is that for to be easiest to compare should IT noise emissions preferably be stated as declared A-weighted sound power level (L_WAd) in bels (B) and not as sound pressure level in decibels (dB) [1,2,3,4,5,6] - something almost no manufacturers did until recently, at least not to end customers.

For the IT equipment product group, where purchasers have had no other means to compare acoustic aspects before buying, global trade is now in the beginning of being facilitated: This since many hardware reviewers have started focusing also on products' acoustic aspects, and some interested manufacturers have started adopting the ISO 9296 standard [1] and labeling their sound power level values for customers.

Many people reading this have probably newer heard of the international standard ISO 9296, sound power level, L_WAd or B (bel).

Most ordinary people simply think of decibel (dB) when they think on noise figures and, as said above, if at all are ordinary people not knowing of a better alternative, used to face IT noise emissions being "declared" in decibel, expressing sound pressure level, and that according to no standard. But the serious ones in the IT industry think in declared A-weighted sound power level in bels per ISO 9296. So there is at this point a discrepancy between how ordinary people and the serious part of industry think on noise level measures, and there is no doubt that the latter know best.

Anyone can obtain simple sound pressure level figures using a cheap sound pressure level meter, but it now costs manufacturers about $600 - 1200 to measure (ISO 7779) and have a product declared according to ISO 9296 in a qualified acoustic laboratory. This is probably the main reason why at this point most purchasers, OEM manufacturers included, don't know anything or know too little about sound power level measures, and why they are used to only face misleading non-standardized non-comparable non-verifiable sound pressure level figures.

Today's high price for ISO 9296 declaration depends on its rare utilization, which results in low competition between acoustic facilities.

Freedom of competition requires that there is something to compete for: A low level of something unwanted is of course an aspect of product quality that complies with this basic prerequisite.

The sustainable solution for freedom of competition on maximizing the acoustic aspect of IT ergonomics is, like for purchasers' freedom of choice, that interested manufacturers adopt the ISO 9296 noise declaration standard. Building quiet IT costs a little extra, as do adoption of the ISO 9296 standard. Since most buyers today aren't used to asking for standardized noise emission declarations for any products at all, information technology equipment included, their now increasing awareness will provide the breaking-point when it becomes even more profitable to build quiet products.

However, at present it's not obvious that industry, here not only speaking on the IT industry, takes an interest in freedom of competition to minimize unwanted sound emissions from its products: This assumption is based on the fact that manufacturers themselves easily could be the ones to inform their customers on the value of their use of international noise declaration standards, but until now most commonly ignore to. The work towards a voluntary universal easy to use product noise declaration standard that takes sound quality aspects in account also show very slow progress: Invented already in the 1930s, the A-weighting filter still represents the only commonly used little effort to adjust dB and B figures to how humans in common apprehend different sounds. Sound quality metrics are only rudimentary covered with A-weighting.

The World industry does have the power to change this state of things, in order to reform the acoustic comfort market place.

Many of the World's governments express a deep concern regarding noise issues. In the industrialized part of the World have government concerns often resulted in regulations for levels of unwanted sound.

Probably have government regulations here sometimes been contraproductive: Noise has tended to be seen as a government problem, instead of a market for acoustic comfort: An approach for natural reasons disliked by industry. It also seems like governments often have lacked the acoustic competence necessary for sustainable decisions in this field. So can it be, that we still haven't invented a universal easy to use and still accurate language to speak of unintentional technology sound.

In the mean time can we use the best we have: The IT industry has reasons to be very proud for having invented the World's most ingenious noise declaration standard specifically for its product group: ISO 9296 not only prioritizes accuracy over good-looking figures, but also intelligently separates the less important sound pressure level figures from the more valuable sound power level ones.

ISO 9296 [1] values are not too difficult for customers to understand. Everyone that is capable of buying and using a PC will also, when properly informed, be capable of making buying decisions according to today's ISO standardized declaration of IT noise emission data:

The lowest possible values of x are what is desirable if searching for a quiet product; Idling values are the most important to keep low. Other modes than Operating and Idling, which traditionally have been used, can be added. The Sleep mode has here been added, because the quite easy achieved goal total silence in Sleep mode encourages IT manufacturers to produce more comfortable and yet less power demanding products. See also US President George W. Bush's Executive Order 13221.

B stands for bels and does here express declared A-weighted sound power level. One bel equals ten decibels (1 B = 10 dB), but bel is according to ISO 9296 preferred when talking on sound power level values for information technology equipment: This because it makes it easier to separate sound power level values from sound pressure level figures. A difference of 0.2 B is clearly noticeable. Lowering the sound power level by 0.9-1.1 B units means a 50 percent reduction of an object's "noisiness". Note that, due to mathematics, a silent object has to be declared as "silent", "inaudible" or  - ∞ B, ie "minus infinity bel". A 0 B or 0 dB product is not a silent product.

ISO 9296 also states how to declare sound pressure level figures, but since they aren't well suited for comparison of noise emissions between products [1,2,3,4,5,6,8] and therefore tend to add confusion, are they here intentionally left out. You can read more in detail on IT noise declaration, and learn how to use sound power level in bels, at the ISO 9296 page.

On the contrary to the thoughts at the Silent PC Web site are most of today's ecological, ergonomical, environmental and industrial quality logo labeling schemes setting noise limits for information technology, but not asking manufacturers to provide their customers their actual emission data. All these labeling schemes, which include noise as a parameter, use the ISO 9296 standard for noise emission declaration; so it would be most easy to also ask manufacturers to provide these values directly to customers, and let them decide what is an acceptable level of unwanted sound emissions. Setting noise limits doesn't counteract the possibility to declare noise emissions.

Labeling schemes trying to regulate noise emission levels of information technology have until now for some reason mostly resulted in lack of industry adoption. Their noise limits have also no relation to the fact that information technology equipment fast has become part of quieter areas than some sort of average acoustic environments. Lastly does the ISO 9296 standard, but not these labeling schemes, comply with the also by the IT industry heavily promoted "One Standard - One Test, Supplier's Declaration of Conformity" (1-1SDoC or 11SDoC) concept [9]; something all involved participants - governments, manufacturers, resellers and their customers - benefits of.

In 2001 Intel®, one of the World's most important IT manufacturers, stated that a declared A-weighted sound power level in Idling according to ISO 9296 of 4.0 B represents "a good trade off between acoustics, performance and cost." [6]. Interestingly enough, all today's IT ergonomics and environment labeling schemes still allow higher noise levels than Intel's target value.

A little more on IT noise limits and 1-1SDoC can be read at the ISO 9296 page.

The special properties of low-intensity acoustic noise emissions implies the possibility of either to overdesign or to underdesign products for their intended contexts. Overdesigned too quiet products cost unnecessary money, while underdesigned too noisy products cost human brain energy.

The special properties of low-intensity acoustic noise emissions constitute the main reason why it is better to declare them to purchasers than to try to set general limits for when they might be acceptable. Noise declaration minimizes the risk of both overdesign and underdesign.

Below follow examples of what some important companies, ergonomic labeling schemes and governments think and do about noise emissions.

Some of the sources are commented because of their ambiguousness or their lack of conformance with international standardization - This because it confuses purchasers and therefore counteracts purchaser awareness; which in turn counteracts freedom of competition regarding the possibility to improve the acoustic aspect of IT ergonomics. The examples below, however, all represent thoughts by some ones who at least have acknowledged unwanted sound an issue.

Note that The Silent PC is an independent publication and has not been authorized, sponsored, or otherwise approved by any of the companies or other sources at the site mentioned or cited.

Dell is one of the World's most important computer systems and information technology companies; well-known for its concept to sell computer systems directly to end-customers. Among the initiated Dell is also known for some clever designed low-noise computers. That Dell is a conscious manufacturer shows in that it is one of the first IT companies presenting industry standard noise declarations according to ISO 9296 for all products easy accessible for customers.

"Dell voluntarily declares its product performance of environmental aspects for Dell products through Dell Environmental Data Sheets. Environmental performance data includes information on product energy consumption, acoustics emissions, materials, eco-labels and approvals, upgradeability/extendibility, and end-of-life management."

Here are all Dell Environmental Data Sheets.

When Dell writes on product testing it states: "In order to meet eco-label requirements and customer expectations, Dell systems are tested for energy consumption, acoustics, and visual ergonomics in Dell's internationally certified state-of-the-art acoustics test facility, located in Austin, Texas. The acoustics facility is an accredited acoustic test facility under the National Voluntary Laboratory Accreditation Program (NVLAP) administered by the National Institute of Standards and Technology and conducts testing according to widely respected ISO test guidelines."

The image shows measurement of sound quality aspects at Dell's NVLAP accredited laboratory. There are two more images from this facility at the ISO 9296 page.
Courtesy and © Dell Computer Corporation.

Comment: Dell not only declares according to ISO 9296, but also strives to optimize sound quality aspects of its products; important aspects which are not yet covered by this standard. Dell also deserves an extra compliment for leaving out customer-confusing talking about noise measurement standards in its data sheets, thus for the moment being one of a few IT manufacturers showing total conformance with the requirements of ISO 9296.

Dell and the Dell logo are trademarks or registered trademarks of Dell Computer Corporation.

IBM, International Business Machines Corporation, is the world's largest information technology company. Here IBM writes on noise and healthy computing:

"..Noise can be very distracting and prevent concentrated mental work. In extreme cases, it can also result in physical disorders."

"..As workstations continue to migrate from the computer room to the quiet office, acoustical noise becomes an increasingly important concern to both users and designers alike. Acoustical noise is considered a human factor because it affects such factors as a workers comfort, job satisfaction and performance. Noise has several adverse effects on human beings. On the physiological side, these effects include hearing damage and hearing loss. On the psychological side, they include interference with speech communication, impairment of performance, and annoyance."

Web-Based Product Noise Declarations is a recent and most impressing article written by IBM acoustic specialists. It covers a proposed program for making standardized noise declarations for both industrial and consumer products. The proposal is aimed at the information technology industry in particular but is generally applicable to all industry groups.

What is an Acoustical Noise Declaration? - a document where IBM explains the benefits of standardized noise declarations.

Here IBM shows that they not only speak about the benefits of Web-based product noise declarations, but actually are implementing it.

Comment: It is hoped that all of IBM will choose to conform with its skilled acoustic specialists' valuable proposal. In December 2004 China's Lenovo Group signed a definitive agreement to acquire IBM's personal computing division. For the present there is no available information on the Lenovo Group's attitude to the IT noise issue.

IBM is a registered trademark of International Business Machines Corporation in the United States and other countries.

Hewlett-Packard (HP), incorporated in 1939, may 2002 merged with Compaq Computer Corporation®. The combined new HP company now constitutes the World's biggest maker of computers and printers. As early as in 1997 did Hewlett-Packard make this impressive statement on IT acoustics:

"To allow reliable noise comparisons between different PCs, Hewlett-Packard hopes other manufacturers will also start to publish acoustic power values according to ISO 7779."

The Hewlett-Packard noise statement can be found in a most instructive white paper named "hp PCs and acoustic noise". Here they also write:

"Noise pollution is a growing problem in our society today. In everyday life we have to tolerate high levels of noise, such as that of traffic, factory workplaces, and busy shopping centers. To concentrate, however, we need a quiet work environment. Personal computers in the office do create noise and can be distracting."

Comment: HP declares some of its products according to ISO 9296. These data can be found below the heading Product Environmental Profiles. Note that much of this information is rather old: You get the impression that HP doesn't keep all its noise declarations uptodate. Also note that ISO 7779 is a measurement standard intended for acoustic specialists, not for IT equipment purchasers. It is, however, frequently confused with ISO 9296, which is the noise declaration standard; ie the interface where manufacturers and their customers can meet. ISO 9296 only states to report according to itself.

HP, Hewlett-Packard, Compaq and the HP Invent logo are registered trademarks or trademarks of Hewlett-Packard Company.

Intel is one of the World's most important companies in PC hardware manufacturing and specifications. Intel has a long tradition in working for improved PC acoustics. An example is where Intel write on Active Hardware Monitoring and Control for Quieter Desktop PCs. Here this important manufacturer states:

"Domestic, international, and industry standards are all demanding better PC acoustics."

An other example on Intel's longlasting efforts in the direction for quieter PCs is found in the the PC 99 System Design Guide:

"Intel and Microsoft are working on proposals for acoustic noise measurement and reporting procedures for PCs. The goal is to achieve common PC acoustic noise measurement methods based on established international standards. With such methods in place, end users will be able to receive reliable acoustic noise specifications about PCs similar to those available for other product categories such as automobiles and appliances.

Although this requirement does not specify noise limits PCs in idle and working states, manufacturers are encouraged to design systems that operate as quietly as possible, especially PCs designed for use in the home family room."

Acoustic Overview is a valuable document at Intel's Desktop Form Factors site:

"As the performance of PC's increase and move from under the desk to other environments, acoustics are quickly becoming a critical part of system design. This document provides background on the science of acoustics, the key areas of the system for concentration, as well as an example design process."

Intel is a registered trademark of Intel Corporation in the United States and other countries.

Microsoft is the World's most important software manufacturer, well-known for its successful Windows® family of operating systems. Microsoft also manufactures some pieces of IT hardware, like mice and keyboards, and recently also a game-playing console, the Xbox®. From about 1998 to 2001 did Microsoft at this url say:

"..Microsoft believes it is critical to achieve quieter operation in PCs.." "..It is expected that the summary "declared acoustic noise emission values" will be made available by manufacturers to consumers in a standardized form. No time frame has yet been established for noise limits as part of the "Designed for Microsoft Windows" logo program, but this is still being examined by Microsoft as a long-term objective.."

In the early months of 2002, but possible as early as in 2001, to about May 2002 did Microsoft at this url talk on "Designing a consumer desktop PC optimized for Microsoft Windows XP" and they made this statement:

"Best Practice: System meets PC Design Checklist guidelines for quiet operation
The PC should be as quiet as possible so that it is welcome in the kitchen, bedroom, and living room, based on the following guidelines:

May 2003 Microsoft talk about "Athens"; a conceptual product in cooperation with Hewlett-Packard®:

"The negative effects of high acoustic emissions from PCs not only interfere with audio quality, they also can affect user productivity and even create potential health risks."

"The "Athens" PC design goal for acoustic emissions is 30 dB or less in A-weighted sound pressure (as defined in ISO 7779 and ISO 9296) while all components except the optical drive are operating."

Comment: In the "Best practice-statement" Microsoft didn't conform with ISO 9296: According to this standard dBA is not what should be used when stating sound power level measures for to compare IT equipment with IT equipment. In the "Athens-statement" Microsoft set a noise level goal in sound pressure level figures. This is not wrong, but a pity, since sound power level is industry standard while sound pressure level isn't. Sound pressure level figures according to ISO 9296 cost as much as the sound power level figures, but are less valuable for product comparisons.

The Silent PC Web site author hopes that the successful Microsoft company will prioritize exact consistency with international standardization in its future unwanted sound writing: This for to aid in reducing the common confusion surrounding the subject. It would also be a most valuable extra bonus if Microsoft choosed to promote the market-driven alternative for to bring low-noise IT equipment to those interested in paying for it: Noise emission declaration according to ISO 9296 to end-customers can be included as a voluntary option in Microsoft's quality logo programs.

Microsoft, Windows and XBox are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.

Statskontoret, the Swedish agency for public management, provides support to the government and government offices. Its task is to conduct studies and evaluations at the request of the government, and also to modernize public administration with the use of IT. Standardization for IT procurements is one of this agency's important jobs:

Statskontoret's Technical Standard 26:6 - Acoustical Noise Emission of Information Technology Equipment - TN 26:6 - is ever since it was created in 1984, and several times updated, the World's most important standard for acceptable upper noise limits for information technology equipment used in homes, offices and data processing centers. While all other ergonomic labeling schemes, and manufacturer quality logo schemes, assume that there exist some sort of average acoustic environment, does Statskontoret's Technical Standard 26:6 divide its recommendations in to three different categories, where the the Category III products are the ones intended to be used where low-noise working conditions are required.

Statskontoret's Technical Standard 26:6 was last updated July 1, 2004. The main changes are that some new types of equipment have been added and that, "because of the technical development, it has been possible to lower many of the highest recommended values for Category II and III equipment." Noise declaration per ISO 9296 is of course also used in TN 26:6.

AMD, Advanced Micro Devices, Inc, is the World's second most important PC processor (CPU) manufacturer.

With the introduction of the Athlon 64 processor AMD in 2003 introduced a technology named "Cool’n’Quiet™". This technology slows the processor and its cooling fan down when the CPU demand is low. This way Cool’n’Quiet™ both can save electric power and reduce noise emissions. AMD regards low noise emissions part of a good working environment:

"Cool‘n’Quiet™ technology to minimize heat and noise for a better working environment"

Comment: The Athlon 64 processor series is the one most often recommended for building high performing quiet PCs. Symtomatically, for an industry that yet hasn't adopted a systemwide approach to the PC system unit's thermal, power consumption and acoustic challenges, have many motherboard manufacturers still not added support for AMD's Cool’n’Quiet technology. Here is a SilentPCReview list of the boards that now can take use of AMD's Cool’n’Quiet technology.

AMD is a registered trademark and Cool’n’Quiet is a mark of Advanced Micro Devices, Inc.

VIA Technologies, Inc. is an important innovator and developer of PC core logic chipsets, microprocessors, multi media and communications chips. In 2001 they launched a family of PC processors (CPUs), the VIA C3, that could perform well without the need of an active noise emitting cooling solution. The C3 processor family has since then been accompanied by the Eden and Antaur CPU families. VIA's new tiny Eden-n CPUs include some most advanced power management and security features, and runs at an extremely low power consumption: What about 1 GHz at 7 watts on a mainboard measuring only 12 x 12 centimeters?!

This conscious manufacturer has also built a most impressive Web site on low-noise computers named "Quiet Computing From VIA":

"Large, overpowered PCs require many high-speed fans to ventilate and cool them and the result is excessive PC noise. Much of the PC industry's scarce resources are being directed at silencing these fans and coolers as a treatment for PC noise. VIA's highly efficient processor platforms target the issue of PC noise at the source because they require minimal noisy forced air-cooling and can result in quieter overall PC systems especially when combined with smaller, quieter power supplies."

VIA Technologies promotes adherence to international acoustic measurement and declaration standards. In their important white paper "Noise, Computing and VIA" published in May 2003 they state:

"To create a level playing field for comparing products VIA recognizes that adherence to a standardized noise measurement system is imperative."

Here VIA writes on the home PC market segment:

"Without doubt, the PC market as we know it is changing, and VIA has made no secret of its belief that connected digital media devices for the living space are the "Next Big Thing" for the PC, with perhaps more growth potential than any other existing segment of the market. The VIA philosophy is that Home Entertainment applications require a better experience rather than higher raw performance. Essentially this means just ramping up clock speed is not the answer for this segment of the market. What matters is optimizing performance where it counts, which for the living room is excellent audio and digital video quality, and offering it all in a low noise, low heat package that fits into a small attractive chassis."

VIA, Anataur, Nano-ITX, Eden and the Eden platform logo are trademarks of VIA Technologies, inc.

Analog Devices, Inc. is a well-reputed company in the design, manufacture and marketing of high-performance analog, mixed-signal and digital signal processing integrated circuits used in signal processing applications. In February 2002 they released one of the World's first integrated circuits targeted at minimizing PC acoustic noise emissions at system level: "A "silent PC" movement has emerged, and PC OEM and motherboard manufacturers are beginning to respond to customer demand for quieter PCs, embedded controllers, high-availability servers, and network systems by producing a range of low-acoustics products. With the ADM1027, Analog Devices provides these manufacturers a complete thermal systems sensor that intelligently monitors and controls both thermal management and noise." In the article Differentiating PCs in a 'Toaster World' Intel® and Analog Devices provide some of the latest knowledge on how Man reacts to noise, rules out the important relation between heat and noise, and how PC noise can be minimized by letting Analog Devices' dBCOOL™ chip control fan rotation speed according to need. Here is an EE Times article on Analog Devices - "Analog IC vendors find 'Intel Inside' a safe bet" The Intelligent PCs page explains how Analog Devices' dBCOOL™ circuit and, other manufacturers' similar ones, at little expense in mass production integrated on a motherboard, can minimize PC acoustic noise emissions, improve thermal management and reduce electric power consumption. A particular benefit of Analog Devices' solution, which might not be the same for other chips, is that it takes psychoacoustic considerations in account.

National Semiconductor is the inventor of the SensorPath™ Interface Technology, a new bus targetted at improving PC thermal awareness and control, with the goal to also minimize PC acoustic noise emissions:

"Today’s PCs present an increasingly difficult challenge for thermal management and control. Continued increases in the clock speed of processors, memory, chip set and graphic chips have dramatically raised temperatures inside PCs and increased the demands of hardware monitoring and, at the same time, prices for PCs and components continue to fall. In addition, new requirements such as minimizing acoustical noise, simplifying board routing, and standardizing platform designs add to the complexity of designing a thermal management solution. The situation promises only to worsen with upcoming generations of PCs, as new high-speed buses like PCI Express™ and smaller form factors emerge."

The Intelligent PCs page further explains this subject.

National Semiconductor and National are registered trademarks and SensorPath is a trademark of National Semiconductor Corporation. PCI Express is a trademark of PCI-SIG®

Apple is regarded one of the World's most inventive personal computer hardware manufacturers, and also well known for providing an operating system, MacOS®, and other software with an easy to use ergonomic human interface. Apple has manifested its thoughts on the importance of lowering noise emissions in products like the iMac®, and the now discontinued Power Mac® G4 Cube. Apple provides some reading on its products' environmental attributes and in them, below below the heading "Noise characteristics", you can read the following:

"Acoustical noise is becoming an increasingly important concern to computer users. It affects user comfort and performance, and it may become disruptive and annoying to the user or others in the work environment. For these reasons, Apple is concerned and designs our products to generate acoustical noise levels as low as possible."

Apple's Power Mac G5 machines were June 24, 2003 advertised like this:

"The Power Mac G5 features a modern chassis constructed of anodized aluminum. Inside, an efficient cooling system uses low-speed fans for superquiet operation - twice as quiet as a Power Mac G4."

And like this:

"Fans in the zones spin at very low speeds resulting in a system three times quieter than the Power Mac G4."

The Apple Power Mac G5 machines are from a technical/acoustical standpoint most interesting: They have been equipped with a hardware monitoring and controling "brain", which adjusts cooling in different thermal zones according to need. The Power Mac G5 computers also incorporate an automatic power management technique called bus slewing. Bus slewing is designed to run at high processor and bus speeds and high voltage when the demand on the processor is high, and to run at low processor and bus speeds and low voltage when the demand on the processor is low. Read more on this subject at the Intelligent PCs page.

The Mac Mini is one of the most recent additions to Apple's computers (January 2005). Advertizing the Mac Mini Apple says: "Best of all, Mac mini purrs along at a whisper-quiet sound level, so there’s no reason to hide it under your desk like an old PC to save your ears."

Comment: The Apple Power Mac G5 machines, are now noise declared according to ISO 9296, exactly conforming with the standard! Check here. It is hoped that this marks a new trend by Apple. The Apple claims regarding low noise emissions for the Mac Mini seems to be confirmed by independent reviews. G4Noise.com is a web site focusing on Macintosh noise issues.

Mac, MacOS, iMac, Power Mac, Mac Mini and Apple are trademarks of Apple Computer, Inc., registered in the U.S. and other countries.

IT Eco Declaration is a Swedish initiative, and alternative to ergonomic labeling schemes. This declaration standard complies with the 1-1SDoC concept; for many years promoted by the World's IT industry [9]. IT Eco Declaration is now widely used by IT manufacturers, resellers and their customers in the Nordic countries: "IT Eco Declaration helps purchasers and persons responsible for environmental issues to make a professional choice when buying IT and telecom products."

Declaration of sound power level and sound pressure values in Operating and Idling modes per ISO 9296 is included in IT Eco Declaration.

Comment: Declaration of sound emissions in Sleep mode ("ACPI S3" for PCs) will hopefully be included in a future update of IT Eco Declaration: This since encouraging low noise levels or silence in Sleep mode not only at little cost provide better acoustic environments, but most often also is more ecological, because it reduces consumption of power: Pitifully enough, as it seems, a limited resource at this planet. See also US President George W. Bush's Executive Order 13221.

AOpen is an IT hardware company with a particular good reputation for their well-built PC motherboards. November 2002 AOpen proved that they also care about their customers concentration:

"Have you ever had the experience of being bombarded by the enormous noises from your CPU fan while you were enjoying music CD? Or in the still of the night, when you were obsessed in surfing the internet, you wish that this whole fan buzzing thing could stop for just one second? With years of research, involving Electronic, Air Dynamic Thermal, Mechanical Engineering and BIOS, AOpen proudly introduces "SilentTek", the Silent PC Technology, on our new generation of AOpen motherboards."

"..In addition to SilentTek, SilentBIOS technology is also being implemented on some of our motherboard. SilentBIOS controls noise level before OS boot, or during the Jukebox FM and Jukebox CD play time, but in the end will pass the controlling authority to SilentTek after OS boot."

Spring 2005 Aopen introduced a new intelligent feature named "Power Master":

"Power Master is a hardware controller to detect your CPU actual loading. And give your system the real time performance. When the loading is really low, it can lower the CPU current and make the fan slower to provide you the quietest working environment. On the contrary, Power Master will increase the CPU current and overclock in time to provide you the best performance."

Here are the AOpen links: SilentTek, SilentBIOS and the press release. Here's a SilentPCReview of SilentTEK, and here of Power Master.

Fujitsu Siemens Computers is Europe's leading computer company. Below the heading Silence they tell:

"Less noise brings more productivity at no extra cost Do you know the following situation? You work in a quiet room e.g. your office. When you switch off your PC, you suddenly notice how intrusive the background noise was. That is what happens to most people - you only perceive noise when it has stopped."

At the bottom of that page Fujitsu Siemens state: "Fujitsu Siemens Computers - the whisper PCs." It is at the same location also possible to view a most interesting high-quality movie on the benefits of quiet working environments, and to download some valuable reading on PC noise emissions.

Fujitsu Siemens patents related to optimized sound-ergonomy is the xcontrol™ for to reduce CD and DVD rotating speed, and their low-noise fan control reducing the PC operating noise:

"During the last few years an almost unbelievable increase in the performance of PC has been achieved due to rapid developments in processors and other PC components. Highly complex calculations, which hitherto were reserved for Mainframes, can now be carried out in a matter of seconds on PC. Data can be exchanged online via the Internet, even over long distances.

However, the operating noise of the components has been neglected. In many of todays' systems the hard disc, CD-ROM, power supply, processor fan etc... demonstrate noisily just how hard they are working, something which can prove to be more than tiresome during long periods of use, especially in the home."

Comment: Fujitsu Siemens Computers doesn't yet make it easy for customers to compare its products' levels of noise emissions. This is a pity since its computers often receive good test results for low noise emissions. It is hoped that this important IT manufacturer, investing so much efforts in a comfortable quiet computing experience, soon will update its Web site and product technical specifications to also include the important ISO 9296 sound power level noise values.

The Fujitsu Siemens Computers logo is a trademark of Fujitsu Siemens Computers GmbH.

TCO Development is worldwide known for its TCO ergonomic and environmental labeling of computer screens, but TCO Development also sets quality standards for information technology like PC system units, peripherals and mobile phones. With the TCO'99 certification a low computer acoustic noise emission as a mandatory requirement was first introduced. It was updated July 2005:

"Acoustic noise from fans, hard disk drives, etc. can be annoying. To prevent such annoyance, the aim shall be that Desktop computers shall cause a minimum of noise during usage. Many end users are sensitive to noise with different characteristics. To enable the end user to choose a product with a comfortable noise level and acceptable generated frequency characteristics, this information should be declared, together with all other data related to a particular product."

The TCO'05 certification states that system units' acoustic noise emissions shall not exceed L_WAd 4.2 bels when in idling and 4.7 bels in operating mode, if the system unit does not emit any prominent discrete tones, declared according to the ISO 9296 standard.

TCO'05 Notebook Computers also include demands on low noise emissions.

Comment: It is positive to see that TCO Development in its updated certifications now asks manufacturers to provide purchasers their actual noise emission values according to the ISO 9296 standard: This since a target sound power level value, based on some sort of average acoustic environment, always will risk become too high for quiet environments.

SAMSUNG's Hard Disk Drive Division is among the initiated known to produce some very quiet and yet high performing hard disks. In a white paper named Noise Gard™ this important manufacturer writes:

"As HDDs have become more advanced, they have also become excessively noisy. Computer generated noise interferes with the consumers audio/video experience. Also, as many computers are located in bedrooms, the acoustic noise created while downloading at night may disturb a good night's sleep."

"In the SilentSeek™ Technology white paper SAMSUNG's HDD division informs:

"In the past customers have chosen HDD products based on capacity, price and reliability. However, recently, as the application of HDD becomes more diversified, acoustic noise emission has emerged as one of the most important HDD characteristic."

Comment: The Samsung SP1604N was recently choosen the reference quiet high performance 3.5" hard disk for the trusted source SilentPCReview. It is hoped the SAMSUNG group soon will decide to provide comparable and verifiable noise figures for all its most competitive IT products according to the international standard ISO 9296.

Seagate is an important manufacturer of PC storage technology. From about 2001 to 2003 they had the reputation of being the provider of the World's quietest and yet high-performing hard disk series, the Barracuda ATA IV. Not only was this disk series very, very quiet, but the little sound it emitted was regarded pleasant:

"Seagate has performed extensive research and development of both quieter drives and better system designs to minimize the perceived acoustics of drives and systems. Seagate is leading the industry in not only providing exceptionally quiet drives but also understanding how drives sound when they are in systems, and designing methods, models and products to minimize overall system noise. These efforts are resulting in ever-quieter disc drives from Seagate and better system designs by OEMs and integrators, which ultimately results in more satisfied customers and end-users."

Comment: The above is cited from the instructive Seagate document Disc Drive Acoustics, where Seagate at this point seem to forget that the IT Industry has agreed upon to use bel and not decibel when stating sound power level measures, and don't mention the standard they conform to when declaring their products' noise emissions. However, if you check the specs for the Seagate Barracuda Serial ATA V series hard disks will you find sound power level being declared in bels. Seagate was recently known for providing the World's most quiet high-performance hard disk series. Now many users complain that the Barracuda 7200.7 disks aren't quiet enough, compared with the earlier Barracudas. These disks are, however, still regarded quieter than many other manufacturers'. It is hoped that Seagate soon will be able to provide a further improved harddisk series, and also that the company will choose to provide standardized possible-to-compare noise data according to ISO 9296, even if these values at first glance might look less elegant, and even if the rest of the storage industry, at least for some time, will continue to communicate non-comparable non-verifiable figures.

SuSE is an important developer of the Linux® operating system. In an e-mail, here with permission cited, they state:

"SuSE Linux is working in direct conjunction with all major hardware vendors on all new hardware developments. Of course we will also support any efforts to save energy or reduce noise in modern computer systems"

SuSE and its logo are registered trademarks of SuSE AG. Linux is a registered trademark of Linus Torvalds.

The Noise Emission Directive 2000/14/EC relating to the noise emission in the environment by equipment for use outdoors was applied from January 3, 2002. One of the aims with the directive is to provide the public with information on the noise emitted by such equipment by labeling the specified products intended for use outdoors with their guaranteed sound power levels. The label represents the World's first known easy for customers to understand and still accurate noise marking of products measured and declared according to ISO standards. Image courtesy of QNET LLC.
Note: This European Union noise label is only intended for marking of specified products for use outdoors.

Source: Final draft criteria (pdf ~35K) which were voted on at the Regulatory Committee meeting on 29 September 2004. These criteria have been sent for translation and should be published in the EU Official Journal spring 2005.

Comment: The EU 2005 limits for personal computer noise emissions represents the first ecologic/ergonomic label scheme improvement in this field since the 1990s, and conforms well with earlier industry statements on what could be a good compromise between cost and office ergonomics. The European commission can also become even more respected for its intentions to reduce noise emissions if it would choose to work for international freedom of competition in acoustic comfort: This by informing purchasers on their possibility to also make buying decisions according to international ISO and IEC noise declaration standards, and aid in the work for a universal product noise marking standard including sound quality aspects, as outlined at this site's Noise Labels page, where you also can read some more on the EU - noise relation.

The Silent PC web site since 1998 is a mark, was between 2003 and 2004 a trademark, and was between 2005 and 2015 a registered trademark of Tomas Risberg, Sweden. Note that the web site by no means is affiliated with Yamaha® Corporation, which owns the rights to use of the word silent for some international trademark classes in the European Union, and possible also other countries.

More on this subject can be read at the Site Info page.

 Tyst Dator - On noiseless computing in Swedish.

Yamaha is a registered trademark of Yamaha Corporation.

1. International Standard ISO 9296:1988 (E) "Acoustics -- Declared noise emission values of computer and business equipment"

2. Standard ECMA-109 4th edition December 1996 - Declared Noise Emission Values of Information Technology and Telecommunications Equipment.

3. Statskontoret's Technical Standard 26:6, "Acoustical Noise Emission of Information Technology Equipment".

4. "hp PCs and acoustic noise", p 3; How to compare noise levels between PCs.

5. TCO'99 Certification - requirements and test methods for environmental labelleling of system units. Report No. 3.

6. Acoustic Overview, Version 1.0, Intel Corporation®, p 7, Design Goal.

7. Personal communication with Acoustical Society of America's (ASA) Standards Office.

8. International Standard ISO 4871:1996 (E) "Acoustics -- Declaration and verification of noise emission values of machinery and equipment"

9. One Standard - One Test, Supplier’s Declaration of Conformity (11SDoC) Scorecard objectives and concept. ECMA Technical Report TR/83 June 2001.

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