Quiet PC 238601 222148263 2008-06-27T20:05:06Z Zodon 6424546 /* Silencing methods */ Styrofoam not a good sound absorber -need soft and dense (e.g. lead) not rigid and light (styrofome) {{Unreferenced|date=September 2007}} A '''quiet PC''' is a [[personal computer]] that makes little [[noise]]. Common uses for quiet PCs include video editing, sound mixing, [[home server | home servers]], and [[home theater PC]]s. A typical quiet PC uses quiet cooling and storage devices and energy-efficient parts. Like noise, the term "quiet PC" is subjective[http://www.silentpcreview.com/article669-page1.html] and there is currently no standard definition for a "quiet PC". However, a general definition accepted by most is that the sound emitted by such PCs should not exceed 30dB when measured 1 meter away from the computer.{{Fact|date=February 2008}} In addition to the average [[Sound pressure#Sound pressure level | sound pressure level]], the frequency spectrum and dynamics of the sound are important in determining if the sound of the computer is [[Psychoacoustics | noticed]]. Sounds with smooth frequency spectrum (lacking audible tonal peaks), and little temporal variation are less likely to be noticed. The character and amount of other sound in the environment also affects how much sound will be noticed or [[Psychoacoustics#Masking effects | masked]], so a computer may be quiet with relation to a particular environment or set of users.[http://www.silentpcreview.com/article669-page1.html] ==Causes of noise== The main causes of PC noise are: # Mechanical friction noise generated by micro motors and fan bearings, as well as vibration noise from low quality chasis and improper assemblies. # Noise generated by electrical coils used in [[power supply|power supplies]] or on [[motherboard|motherboards]]. Noise in personal computers has been increasing with rising computing power and number of transistors on a single [[die (integrated circuit)]]. More transistors of a given size use more power, which releases more heat. Faster-rotating cooling fans are one common way to remove this heat. Also, motor rotation speed for [[hard disc drive]] (HDD) and [[Optical disc drive]] (ODD) has been rising for faster data processing with technical advances in micro motors. Faster rotation (usually measured in [[RPM]]) causes higher bearing friction, thus more noise, given the same bearing technology. The noise issue had received widespread attention with [[AMD]]'s early Athlon CPUs and [[Intel]]'s Pentium 4 [[Pentium 4#Prescott|Prescott]] core CPU known for its excessive heat and bundled fan noise running on high [[RPM]]. With the introduction of Home Theatre PCs ([[HTPC]]), the excessive heat and noise problem, that had been mostly confined to the overclocking and quiet computing communities, came to the attention of the general public. The main approaches to reducing noise problems from personal computers are: # Reduce heat generation by using energy efficient parts - nearly all the energy used by a computer is converted into heat. # Improve cooling - by using more efficient cooling parts and lower friction, quieter bearings. # Use [[Soundproofing]] to reduce the effects of remaining noise sources. ==Silencing methods== Common silencing methods include: * Replacing [[heat sink]]s with more efficient models. This often entails the use of larger copper or aluminum heat sinks which may incorporate [[heat pipe]]s. * Replacing fans with passive cooling solutions where possible, such as fans on motherboards and GPUs. * Replacing fans with low-speed, large-diameter fans with low bearing and motor noise. Larger fans can move more air per revolution than smaller fans. * Mounting fans on anti-vibration mounts. * Replacing the [[power supply]] with a quieter model. The main considerations, from a noise-reduction point of view, in choosing a power supply are fan quality, AC/DC conversion efficiency, and how good the thermal fan speed control is at keeping the fan running slow and steady. Efficiency is important because the less heat that is produced the less work the fan has to perform. * Replacing hard drives with quieter models. Hard drives can also be replaced with laptop hard drives, with solid state devices like [[compact flash]] or networked file systems like [[Network File System (protocol)|NFS]]. * Covering the case with [[Soundproofing | sound insulation]] material such as rubber, foam or fiber mat, although this method has limited effectiveness. The material can (because of its weight) dampen case resonance, and can also absorb some high-frequency sound. Care must be taken to be sure the soundproofing does not interfere with airflow and cooling. * In energy-hungry computers, [[water cooling]] may be necessary for quiet operation. Older water pumps sometimes can make systems noisier than air-cooled, low-power computers. However, recent advances in 12v DC pump technologies has resulted in many pumps being inaudible. In a modern watercooling system geared towards silence rather than performance, the loudest component in the computer is often the [[Hard Drive]] or [[Optical disc drive]] when performing accesses to the media. * Placing a dampening material around hard drives (or other spinning drives) such as [[Sorbothane]] Low/no cost methods: * [[Undervolting]] CPUs. Many of today's CPUs can run stably at their stock speed, or even with a slight overclock, at a reduced voltage, which reduces heat output. [[Underclocking]] can be done for the same effect, however this reduces performance and is not as effective as undervolting; all the same, underclocking may allow further undervolting. Power consumption is approximately proportional to ''V<sup>2</sup>·f'', that is, it varies linearly with the clock frequency and quadratically with the voltage.<ref>J. M. Rabaey. Digital Integrated Circuits. Prentice Hall, 1996.</ref> This means that even a small reduction in voltage can have a large effect in power consumption. Undervolting and underclocking can also be used with [[chipset]]s and GPUs. * Reducing fan speed. This is easily done for fans with [[Molex]] connectors [http://www.silentpcreview.com/article6-page1.html]. With 3-pin fans, either fixed inline [[resistor]]s or [[diode]]s, or commercial [[Fan control|fan controllers]] such as the [[Zalman]] Fanmate can be used. Software like [[speedfan]] may allow fan speed control. Many newer motherboards support [[Pulse-width modulation]] (PWM) control, allowing the fan speed to be set in the [[BIOS]] or with software. * Replacing the fan in the [[Power supply|PSU]] with a quieter one (which still offer adequate airflow to cool the PSU), or undervolting it. Note that opening a PSU can be dangerous. * Removing restrictive fan grills to allow easier airflow. * [[Cool'n'Quiet#Enabling Cool'n'Quiet|Enabling Cool'n'Quiet]] for [[AMD]] CPUs or [[EIST]] on [[Intel]]'s CPUs. * Using software such as [[Nero AG|Nero]] Drivespeed to reduce the speed of [[optical drive]]s. * Isolating hard disk noise, either by using anti-vibration mounts (generally rubber or silicone grommets), or by suspending the hard disk to fully de-couple it from the PC chassis (generally mounting it in a 5.25" [[drive bay]] using high-grade elastic). * Setting the hard disk's [[Automatic Acoustic Management|AAM]] value to its lowest setting. This reduces the seek noise produced by the hard drive, but also impacts performance slightly. * Setting operating system to spin down hard drives after a short time of inactivity. This, however reduces drive's lifespan and commonly conflicts with the OS and running programs, though it can still be useful for drives which are only used for data storage. * Defragmenting the hard drives to reduce the drive heads' need to search widely for data, also improves performance. * Arranging components and cables to improve airflow. Wires hanging inside the computer can block the airflow, which can increase heat. They can be easily moved to the side of the case so that air can pass through more easily * Removing dust from inside the computer. Dust on computer parts will retain more heat. Fans draw in dust along with outside air, it can build up quickly inside the computer. Dust can be removed with a vacuum, [[Gas duster|gas duster]] or air compressor. Special anti static vacuums should be used however to prevent [[Electrostatic Discharge]]. Ideally this would be done at least twice every year. ==Sound Power Measurement== Though standards do exist for measuring and reporting sound power output by such things as computer components, they are often ignored.[http://www.silentpcreview.com/article121-page4.html][http://www.silentpcreview.com/article28-page1.html] Many manufacturers do not give sound power measurements, and those that do often do not specify how sound power measurements were taken. Even such basic information as measurement distance is rarely reported. Without knowing how it was measured, it is not possible to verify these claims, and comparisons between such measurements (e.g. for product selection) are meaningless. Comparative reviews, which test several devices under the same conditions are more useful. Although even then, an average sound pressure level is only one factor in determining which components will be perceived as quieter.[http://www.silentpcreview.com/article669-page2.html] ==Individual components in a quiet PC== The following are notes regarding individual components in quiet PCs. ===Cases=== {{main | Computer case }} [[Image:Silent PC-Antec P180.JPG|thumb|Antec P180, with isolated chambers for more segregated airflow.]] [[Image:Antecp180b.JPG|thumb|Another example of the Antec P180, this one demonstrating the use of the Scythe Ninja, a fanless CPU cooler.]] Cases designed for low noise usually include reasonably quiet fans, and often come with a relatively quiet power supply. Some cases for quiet computers incorporate heatsinks to cool components passively.[http://www.silentpcreview.com/article301-page1.html] Cases that provide lots of space make it easier to quiet a PC, both by allowing for airflow and by accommodating large coolers. ====Case Airflow==== Noise optimized cases like the [[Antec]] [http://www.silentpcreview.com/article255-page1.html P180] and Antec [http://www.silentpcreview.com/article272-page1.html P150] often have ducting and partitioning within the case to optimize airflow and thermally isolate components. For example, the P180 has the PSU mounted in the bottom of the case in an isolated partition. This design feature allows cooler air to enter the PSU, reducing the necessary airflow and accordingly, the noise output of the fan. Apple has also employed this tactic in their G5 workstations in an effort to reduce noise. Antec's ''Sonata'' is often considered by the mainstream to be one of the quietest PC cases; however, it has since been surpassed by the P180 and other more-advanced cases. [http://www.silentpcreview.com/article75-page4.html] Vents and ducts may easily be added to regular cases.[http://www.silentpcreview.com/article293-page2.html] More obstructive fan grills increase pressure drop and lower airflow, necessitating higher fan speeds and more noise output. They also increase the turbulence of the flow, which causes some noise of its own. Cases designed to be quiet typically have wire grills or honeycombed fan grills, which perform almost as well as wire grills; both are far superior to the old style of stamped grill. Features that facilitate neat cable management, such as brackets and space to run cables behind motherboard tray, help increase cooling efficiency. ====Case Soundproofing==== The inside of a case can be lined with [[Soundproofing | dampening materials]] to reduce noise by: * attenuating the vibration of the case panels via extensional damping or constrained-layer damping. * reducing the amplitude of the vibration of the case panels by increasing their mass. * absorbing airborne noise, such as with foam. ===Cooling Systems=== {{main | Computer cooling}} ====Heat sinks==== {{main | Heat sink}} Heat sinks that operate efficiently with little airflow are often used in quiet computers. Typically they are (relatively) large, and have larger spaces to allow freer airflow. Often [[heat pipes]] are used to help distribute heat. For instance, in 2007, the Scythe Ninja or the [[Thermalright]] Ultra-120 were frequently used as CPU heat sinks in quiet computers.[http://www.silentpcreview.com/article251-page1.html] [http://www.silentpcreview.com/article30-page1.html][http://www.silentpcreview.com/article30-page1.html] ====Fans==== {{main | Computer fan}} [[Image:Silent PC-large fan.JPG|thumb|A 120 mm variable speed fan.]] Bearing and motor noise vary between different fan models and often between different samples of the same model. Quiet PCs typically use larger (e.g. 120 mm) low-speed fans. Although 140 mm fans are made by some manufacturers, such as Aerocool and Yate Loon, there are very few cases or heatsinks that can use them. Fan adapters, which allow larger fans to be used in place of smaller ones, and fan brackets, like the Zalman FB123, often help when replacing small fans. [http://www.nexustek.nl Nexus], [http://www.ebmpapst.co.uk/pages/content.asp?s_52,p_2 Ebm-papst], Yate Loon and some Scythe fans are generally considered the quietest fans as of 2006.{{Fact|date=February 2008}} In situations where the resistance to flow is very low, like in free-air conditions, Noctua fans also perform very well. It must be noted that certain brands of fan are prone to unsavory "testing" methodologies, ''e.g.'' noise output is measured at an unusually long distance.{{Fact|date=February 2008}} Extensive comparative surveys have been posted by Silent PC Review[http://www.silentpcreview.com/article695-page1.html] [http://www.silentpcreview.com/article63-page2.html] and MadShrimps.[http://www.madshrimps.be/?action=getarticle&articID=421] [[Fan control|Fan controllers]] can be used to slow down fans and to precisely choose fan speed. Fan controllers can produce a fixed fan speed using an inline resistor or diode, or a variable speed using a [[potentiometer]] or [[Pulse width modulation|Pulse Width Modulation]] (PWM). Resistor-based fan control feeds the fan a lower voltage, while PWM fan control rapidly cycles between feeding the fan full voltage and no voltage. PWM fan control reduces rotational speed, but can also produce clicking sounds in some fan models. Fans can also be plugged into the power supply's 5 volt line instead of the 12 volt line (or between the two for a potential difference of 7 volts, although this cripples the fan's speed sensing) to run them at a reduced speed[http://www.silentpcreview.com/article6-page1.html]. Most fans will run at 5 volts once they are spinning, but may not start reliably at less than 7 V. Some simple fan controllers will only vary the fans' supply voltage between 8 V and 12 V to avoid this problem entirely. Some fan controllers start the fan at 12 V, then drop the voltage after a few seconds. Soft mounting fans (e.g. with rubber or silicone fan isolators) can help reduce transfer of fan vibrations to other components.[http://www.silentpcreview.com/article262-page1.html] Intel has recently developed a piezoelectric fan for use in desktop PCs, which is quieter than motor fans and consumes a fraction of the power.[http://electronics-cooling.com/articles/2007/feb/a1/] ====Watercooling==== {{main | Watercooling}} Watercooling is a method of heat-dissipation by transferring the heat through a conductive material which is in contact with a liquid, most often demineralised water and an additive to prevent bacterial growth and provide cosmetic effects. This heated water travels in a loop which usually contains a reservoir, radiator and pump. Recent advances in 12v DC pump technologies (for the first time specifically geared-for pc development) allow for new pumps to be both extremely powerful and extremely quiet. Loops can be made up of any combination of these items and some aren't required such as the radiator or reservoir if alternatives methods are used. The radiator often uses two or more fans to air cool the radiator fins and dissipate the majority of the heat at this point. The most common loop order is reservoir to pump, radiator then the watercooling block and back to the reservoir. The radiator and fan efficiency has the greatest effect on the noise level and cooling efficiency but watercooling is currently the most effective and potentially quietest methods of cooling above ambient temperatures. There is an inherent danger in the use of liquid around electrical equipment and leak testing the loop is always recommended before attaching any parts to the motherboard, after all loop connections have been made. The 12v DC pump can be run using batteries or a psu making sure no power is going to any other part of the system. Because of these risks and the use of water under pressure watercooling is a greater technical challenge to set up due to the number of components and case modification usually required. ===Power supplies=== {{main | Computer power supply }} [[ Computer power supply | PSUs]] are made quieter through the use of quieter fans, more intelligent fan controllers (ones for which the correlation between temperature and fan speed is more complex than linear), higher efficiency, which reduces waste heat and need for airflow, more effective heatsinks and through designs which allow air to flow through with less resistance. PSU Efficiency has been generally improving.[http://www.80plus.org] Selecting a power supply of appropriate wattage for the computer is important for high efficiency and minimizing heat. Power supplies are typically less efficient when lightly or heavily loaded. High wattage power supplies will typically be less efficient when lightly loaded, for instance when the computer is idle or sleeping. Most desktop computers spend most of their time lightly loaded.[http://www.silentpcreview.com/article699-page1.html] For example, most desktop PCs draw less than 250 watts at full load, and 200 watts or less is more typical.[http://www.silentpcreview.com/article28-page4.html] Power supplies with thermally controlled fans can be made quieter by providing a cooler and/or less obstructed source of air. For instance, the power supply is in a separate compartment in the Antec P180 to keep the air supplied to the PSU cool. The fan in a power supply can be replaced with a quieter one, although there is a risk of electric shock when doing this, and it usually voids the warranty. Fanless power supplies are available. * Some of them are equipped with large passive heat sinks and rely on convection or case airflow to dissipate heat. It is also imperative that such fanless power supplies be installed in a case with good ventilation.[http://www.silentpcreview.com/article699-page1.html] * There are also fanless DC to DC power supplies that operate like those in laptops, using an external power brick to supply DC power, which is then converted to appropriate voltages and regulated for use by the computer.[http://www.silentpcreview.com/article601-page1.html] These power supplies usually have lower wattage ratings. The electrical coils in power supplies can produce noise which can become noticeable in a quiet PC. ===Motherboards=== {{main | Motherboards}} [[Image:Silent PC-Northbridge chipset.JPG|thumb|Passively cooled northbridge chipsets help reduce noise.]] Many modern motherboard chipsets have hot [[northbridge]]s (notably [[nForce4]]), which may come with active cooling, usually a small, noisy fan. Fanless heatsinks, such as the [[Zalman]] ZM-NB47J, ZM-NBF47 or the [[Thermalright]] HR-05, may be used to eliminate a noisy chipset fan.[http://www.madshrimps.be/?action=getarticle&number=1&artpage=1971&articID=473][http://www.silentpcreview.com/article30-page2.html] Some motherboard manufacturers have got rid of these fans by incorporating large heatsinks or [[heatpipe]] coolers, however they still require good case airflow to remove heat. Also, motherboard [[Voltage regulator | voltage regulators]] often have heatsinks and may need airflow to ensure adequate cooling. Motherboards can also produce coil noise. [[Undervolting]] and [[underclocking]] generally require motherboard support. Some motherboards can control the fan speed using software like [[speedfan]]. Most recent motherboards have built in PWM based fan control for one or two fans. ===CPUs=== [[Image:Silent PC-CPU fan.JPG|thumb|A large copper heatsink and high flow fan provide exceptional cooling for the cooler-running Pentium 4 Northwood.]] The heat output of a CPU can vary according to its brand and model - to be exact, its [[TDP]]. [[Intel]]'s third revision [[Pentium 4]], using the "Prescott" core, was infamous for being one of the hottest-running CPUs on the market. By comparison, [[AMD]]'s [[Athlon]] series and the new [[Intel]] [[Core 2]] perform better at lower clock speeds, and thus produce less heat. Modern CPUs often incorporate [[Power management | energy saving systems]], such as [[Cool'n'Quiet]], [[LongHaul]], and [[SpeedStep|EIST]]. These reduce the CPU [[Clock rate | clock speed]] and [[CPU core voltage | core voltage]] when the processor is idle, thus reducing heat. The heat produced by CPUs can be further reduced by [[undervolting]], [[underclocking]] or both. Most modern mainstream and value CPUs are made with a lower [[Thermal Design Power | TDP]] to reduce heat, noise, and power consumption. Most of Intel's desktop Core 2 Duo processors have 65W TDPs, and AMD has newer processors with a TDP between 35W and 65W. ====Modern low power CPUs==== Maximum TDP: *[[Athlon 64 X2]]: 45W, 65W, 85W *[[Intel Core]] and [[Core 2]] series: 65W, 85W *Intel [[Pentium M]] and [[Celeron#Pentium M Celerons|Celeron M]] (lacks SpeedStep) *[[VIA C7]]: 12W-20W (Fanless) *[[transmeta]] processors *[[Geode (processor)]]: 5W, 25W *[[Intel Atom]]: 2W, 4W, 8W ===Video cards=== [[Video cards]] can produce a significant amount of heat. A fast [[Graphics processing unit | GPU]] may be the largest power consumer in a computer. For instance, 161 watts peak power consumption for an [[ATI Technologies | ATI]] [[Radeon]] HD 2900 XT 512 [http://www.xbitlabs.com/articles/video/display/radeon-hd-2900-games.html]. Because of space limitations, video card coolers often use small fans run at high speed, making them noisy. Display options for making a quiet computer include: * Use motherboard video output - typically low performance and low power * Select a video card that does not use a fan **many of the more efficient GPUs are available in fanless models[http://www.silentpcreview.com/forums/viewtopic.php?t=14366] **many older video cards used little power, often not requiring heatsinks or fans * Replace the GPU cooler with a larger heatsink[http://www.silentpcreview.com/article30-page2.html] and possibly a larger, slower fan * No video card - use a terminal, [[thin client]], USB display or [[desktop sharing]] software if display required ===Secondary storage=== ====Hard drives==== {{main | Hard drives}} [[Image:Silent PC-silicone grommets.JPG|thumb|Silicone grommets in a computer case for mounting a hard drive to reduce vibration.]] Previously, hard drives used [[ball bearing]] motors, but they got noisy when the rotational speed of the drive was increased to 5400 RPM or 7200 RPM. More recent desktop hard drives use [[fluid bearing]] motors. The first hard drive widely reputed to be quiet was the [[Seagate]] Barracuda ATA IV.[http://www.silentpcreview.com/article29-page2.html] [[Samsung Electronics| Samsung]] and [[Western Digital]] are considered to produce some of the quietest high capacity 3.5" drives as of Winter 2008, with noise varying per model[http://www.silentpcreview.com/section13.html]. The smaller 2.5" form-factor hard drives generally vibrate less, are quieter, and use less power than the traditional 3.5" drives[http://www.silentpcreview.com/article264-page3.html]. On the other hand, they often have lower performance and less capacity, and cost considerably more per [[gigabyte]]. To minimize vibrations from a hard drive being transferred to, and amplified by, the case, hard drives can be mounted with soft rubber studs, suspended with elastics or placed on soft foam or [[Sorbothane]]. Hard disk enclosures can also help reduce drive noise. Care must be taken to ensure that the drive gets adequate cooling. Hard disk temperatures can often be monitored by [[Self-Monitoring, Analysis, and Reporting Technology | SMART]] software. ====Solid state storage==== =====Flash memory===== ======Solid state drive====== [[Solid state drive]] (SSD) storage offers faster seek times, lower power consumption, no moving parts; making it theoretically more reliable and silent. There is scope for very high capacity drives; however, they are currently extremely expensive per GB and are fairly scarce. Samsung [http://www.samsung.com/PressCenter/PressRelease/PressRelease.asp?seq=20060523_0000257520 launched first notebook with their own 32 GB SSD drives on [[May 23]], [[2006]]], the first consumer-oriented SSDs, but still far more expensive and at far lower capacities than traditional drives. ======Compact Flash cards====== A few people use [[Compact Flash]] cards (or "CF cards" for short) for storage. Because they use [[Integrated Drive Electronics|IDE]] protocol, a simple adapter is all that is needed to connect CF cards to function as an IDE or [[PC Card]] hard disk. CF cards are also small, allowing [[Small form factor|SFF]] PCs to be made, produce no noise, use very little power (further reducing heat output in the AC/DC conversion in the PSU), and an insignificant amount of heat. However, they are very expensive per [[Gigabyte|GB]] and are only available in small capacities. There are also issues regarding the maximum number of writes to each sector; often specified as 100,000 write cycles. However, there are industrial grade cards which specify a higher number of erase cycles, and different file systems, or technologies such as [[Enhanced Write Filter]][http://blogs.msdn.com/embedded/archive/2005/10/26/485389.aspx] can reduce the writes to the card. Also, CF cards will fail gradually, so it will be easy to notice before any significant amount of data is lost, unlike the possible immediate failure of HDDs. Due to their small capacities they are easy to back up entirely, and often have 10 year or even lifetime warranties. Windows minimization projects such as [http://www.winimize.com Winimize (Windows 98, less than 20MB)] and [[Linux]] projects such as [[Puppy Linux]] mean that running an OS in small capacity, cheap compact flash card is possible. Because they have many OS components removed they are less prone to [[Computer virus|viruses]] and other [[malware]]. The sustained transfer rate of current CF cards is a maximum of around 25MB/s, compared to an average of around 70MB/s for modern hard drives.[http://storagereview.com] However, the speed of flash memory is increasing at a faster rate than that of hard drives, and they have minimal seek times compared to hard drives, which increases the speed of loading many small files, and makes the PC seem more responsive as most operations performed by the OS include small files. Due to the fast seek times CF cards also don't show the effects of [[file system fragmentation]] like hard drives do. Newer CF cards support faster transfer protocols like DMA. It is possible to use a compact flash card for storing only information that isn't changed very often - such as music, videos and binary executables, while storing the small config files and other frequently modified data on a small hard drive or [[i-RAM]]. ======USB flash drives====== {{main | USB flash drives}} Where a motherboard supports booting from [[Universal Serial Bus|USB]] drives, they can be used in a similar fashion to CF cards to run the OS. With some [[Linux distributions]], it is not much harder than using a CF card. As they both use [[flash memory]], they have the same advantages and disadvantages, however speed is limited by the [[USB#Transfer speed|USB bus]]. =====Gigabyte i-RAM===== The [[i-RAM]] is a solid-state disk which has four DIMM slots to allow regular PC [[Random access memory|RAM]] to be used like a disk. It is much faster than a hard disk, does not have the write cycle limitations of flash memory, however it requires power continuously in order to maintain its contents (from standby power or a battery when the system is off), uses more power than many laptop hard drives, has maximum capacity of 4 GiB, and is expensive. =====Problems and solutions===== All forms of affordable solid state storage offer relatively small capacity. They can be used as main storage for tasks which do not use large amounts of data or large programs, such as web browsing or word processing. Larger files and programs can be stored on a secondary hard drive which is only accessed when needed. Keeping the OS, often accessed files, and smaller programs on a solid state drive means that the hard drives can be powered down much of the time. [[Network-attached storage]], or NAS, is another alternative, allowing loud hard drives to be stored remotely. Small USB drives or CF cards can be used to make the process of network booting easier also. ====Optical drives==== Optical drives can be slowed down by software to quieten them, such as [[Nero_Burning_ROM|Nero]] drivespeed, or emulated by [[Disk image emulator | virtual drive programs]] such as [[Daemon Tools]] to eliminate their noise entirely. Notebook optical drives can be used, which tend to be quieter, however this may be because they tend to run slower (typically 24x CD speed, 8x DVD speed). ===Laptops=== {{main | Laptops}} Laptop computers typically do not have power supply fans, video card fans and they use smaller hard drives. They also use many lower power components. However laptop CPU coolers are usually smaller, so may be noisier than their desktop counterparts. Limited space makes silencing laptops more difficult. A few laptops do not use cooling fans, for instance the Dell Latitude X1[http://reviews.cnet.com/laptops/dell-latitude-x1/4505-3121_7-31320873.html], Panasonic Toughbook W5[http://www.toughbook.eu/media/SpecSheet_CF-W5_en.pdf] and T5[http://www.toughbook.eu/media/SpecSheet_CF-T5_en.pdf], Fujitsu Lifebook P7120[http://www.notebookreview.com/default.asp?newsID=2695]. The [[OLPC XO-1]] has no internal moving parts. ===Monitors=== {{main |Computer display}} [[Cathode ray tube | CRT]] monitors can produce coil noise, as can the power brick for an [[Liquid crystal display | LCD]] monitor. LCD monitors tend to produce the least noise (whine) when at 100% brightness.{{Fact|date=February 2008}} An LCD monitor with a separate "power brick" tucked out of the way will produce less noticeable noise than one with the power supply built into the screen housing. ===Printers=== {{main | Computer printer}} [[Dot matrix printer | Dot matrix]] and particularly [[daisy wheel printer | daisy wheel]] printers were often noisy, and boxes or cabinets were sometimes used to reduce the noise. ==References== {{reflist}} ==External links== * [http://www.silentpcreview.com SilentPCReview.com] hundreds of thoroughly researched articles on various aspects of PC acoustics. ** A good starting point on SPCR is...[http://www.silentpcreview.com/article669-page1.html What is a "Silent" Computer?] ** Followed by [http://www.silentpcreview.com/section5.html Reference/Recommended] and [http://www.silentpcreview.com/forums/viewtopic.php?t=21152 SPCR in a nutshell] * [http://www.dmoz.org/Computers/Hardware/Systems/Quiet/ Open Directory Computers: Hardware: Systems: Quiet] * [http://www.madshrimps.be/gotoartik.php?articID=286 Build a Silent PC] air-cooled * [http://www.silent.se/ The Silent PC] [[Category:Personal computers]] [[Category:Noise pollution]] [[de:Silent PC]] [[es:Silent pc]] [[ja:静音パソコン]] [[ko:조용한 PC]] [[ru:Тихий персональный компьютер]]