Quiet PC

A quiet, silent or fanless PC is a personal computer that makes very little or no noise. Common uses for quiet PCs include video editing, sound mixing and home theater PCs, but noise reduction techniques can also be used to greatly reduce the noise from servers. There is currently no standard definition for a "quiet PC",^[1] and the term is generally not used in a business context, but by individuals and the businesses catering to them.

A proposed general definition is that the sound emitted by such PCs should not exceed 30

Energy Star, in 1992, and similar programs led to the widespread adoption of sleep mode among consumer electronics, and the TCO Certified program promoted lower energy consumption.^[3] Both added features that allowed systems to only consume as much power as is needed at a particular moment and helped reduce power consumption. In a similar manner the first low power and energy-conserving CPUs were developed for use in laptops but can be used in any machine to reduce power requirements, and hence noise.

Causes of noise

The main causes of PC noise are:

• Mechanical friction generated by disk drives and fan bearings
• Vibration from disk drives^[4] and fans
• Air turbulence caused by obstructions in the flow of air
• Air vortex effects from fan blade edges^[5][6]
• LCD monitors.^[7]

Many of these sources increase with the power of the computer. More or faster transistors use more power, which releases more heat. Increasing the rotation speed of fans to address this will (all things being equal) increase their noise. Similarly, increasing hard disk drives' and optical disc drives' rotation speeds increases performance, but generally also vibration and bearing friction.

Measuring noise

Though standards do exist for measuring and reporting sound power output by such things as computer components, they are often ignored.^[8][9] Many manufacturers do not give sound power measurements. Some report sound pressure measurements, but those that do often do not specify how sound pressure 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, but even then, an average sound pressure level is only one factor in determining which components will be perceived as quieter.^[1]

Noise reduction methods

Reducing noise with new CPU cooler

Common noise reduction methods

• Use large, efficient heat sinks
• Incorporate heat pipes, which have much higher effective thermal conductivity than solid copper
• Use fans with lower speeds and larger diameters
• Use fans with low bearing and motor noise
• Rather than constant-speed fans, use thermostatically controlled variable speed fans that run at less than maximum speed, and thus run quieter most of the time
• Use an efficient power supply to minimize waste heat
• Use quieter models of hard drive
• Use solid state devices like
  compact flash
  or solid-state drives rather than traditional mechanical hard drives
• Use remote networked via
  NFS
  rather than local disks
• Place a damping material such as Sorbothane around hard drives or other spinning items
• Use sound insulation material to absorb sound and dampen case resonance
• Water cooling, although difficult to set up, may be useful in some situations

Low-cost methods

A number of methods exist for reducing computer noise at little or no added cost.

• Reduce CPU supply voltage ("undervolting"). 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. Power consumption is approximately proportional to V²·f, that is, it varies linearly with the clock frequency and quadratically with the voltage.^[10] 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 chipsets and GPUs.
• Enable
  EIST) on Intel
  CPUs.
• Reduce fan speed. For newer computers, the speed of fans can be varied automatically, depending on how hot certain parts of the computer get. Lowering a DC fan motor's supply voltage will reduce its speed while making it quieter and lowering the amount of air the fan moves. Doing this arbitrarily could lead to components overheating; therefore, whenever performing hardware work it is advised to monitor the temperature of system components. Fans with
  Argus Monitor 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.
• Mount fans on anti-vibration mounts.
• Remove restrictive fan grills to allow easier airflow, or replace noisy fan grills with quieter versions.
• Use software such as
  optical drives
  .
• Isolate hard disk noise, either by using anti-vibration mounts (generally rubber or silicone grommets), or by suspending the hard disk to fully decouple it from the computer chassis by mounting it in a 5.25 inch drive bay with viscoelastic polymer mounts.
• Set the hard disk's
  AAM
  value to its lowest setting. This reduces the seek noise produced by the hard drive, but also reduces performance slightly.
• Set operating system to spin down hard drives after a short time of inactivity. This may reduce a drive's life span and commonly conflicts with the OS and running programs, though it can still be useful for drives that are only used for data storage.
• Defragment hard drives to reduce the drive heads' need to search widely for data. This can also improve performance.
• Arrange components and cables to improve airflow. Wires hanging inside the computer can block the airflow, which can increase the temperature. They can be easily moved to the side of the case so that air can pass through more easily.
• Remove 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 cleaner, gas duster, or compressed air. Special anti-static vacuum cleaners should be used, however, to prevent electrostatic discharge (ESD). Ideally, this would be done often enough to prevent a significant amount of dust from ever building up. How frequently this would need to be performed would depend entirely on the environment in which the computer is used.

In some cases an acceptable solution may be to relocate the too-noisy computer outside the immediate working area, and access it either with long-distance HDMI/USB/DVI cables or via remote desktop software from a quiet thin client, e.g. based on a Raspberry Pi, a miniature computer that does not even use a heat sink.

Individual components in a quiet PC

The following are notes regarding individual components in quiet PCs.

The motherboard, CPU, and video card are major energy users in a computer. Components that need less power will be easier to cool quietly. A quiet power supply is selected to be efficient while providing enough power for the computer.

Motherboard

A motherboard based on a

Even though a given hardware monitoring chip may be capable of performing fan control,[14] a motherboard manufacturer may not necessarily wire up the fan header pins of the motherboard correctly to the hardware monitoring chip, thus sometimes computer fan control cannot be performed on a given motherboard due to the wiring irregularities, even though the software may indicate that the fan control is available due to the underlying support by the hardware monitoring chip itself.^[15] Other times, it may be the case that a single fan-control setting may affect all fan connector headers on the motherboard at the same time, even if individual settings for each fan are available in the hardware monitoring chip itself; these wiring issues being very common makes it difficult to design good general-purpose user interfaces for configuring fan control.^[15]

Motherboards can also produce

CPU

The heat output of a CPU can vary according to its brand and model or, more precisely, its

Modern CPUs often incorporate

• Replace the stock cooler with an aftermarket one.^[17]
• Use motherboard video output. Typically, motherboard video takes less power, but provides lower gaming or HD video decoding performance.
• Select a video card that does not use a fan.^[18]
• Most modern graphics cards come with tools that allow the user to reduce the power target and adjust fan curves, resulting in quieter operation at a cost of performance

Power supply

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.^[19] For example, most desktop PCs draw less than 250 watts at full load, and 200 watts or less is more typical.^[20]

Power supplies with thermally controlled fans can be made quieter by providing a cooler and/or less obstructed source of air, and fanless power supplies are available, either with large passive heat sinks or relying on convection or case airflow to dissipate heat. It is also possible to use 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.^[21] These power supplies usually have lower wattage ratings.

The electrical coils in power supplies can produce

Equipping the PSU with a power cord that uses a ferrite bead can sometimes help to reduce humming from the PSU.

Case

Case designed for low noise usually include quiet fans, and often come with a quiet power supply. Some incorporate heatsinks to cool components passively.^[22]

Larger cases provide more space for airflow, larger coolers and heat sinks, and sound dampening material.

Airflow

Noise-optimized cases^[23][24] often have ducting and partitioning within the case to optimize airflow and to thermally isolate components.^[25] Vents and ducts may easily be added to regular cases.^[26]

Case designed to be quiet typically have wire grills or honeycombed fan grills. Both are far superior to the older style of stamped grill.

Features that facilitate neat cable management, such as brackets and space to run cables behind the motherboard tray, help increase cooling efficiency.

Air filters can help to prevent dust from coating heat sinks and surfaces, which dust impedes heat transfer, making fans spin faster. However, the filter itself can increase noise if it restricts airflow too much or is not kept clean, requiring a larger or faster fan to handle the pressure drop behind the filter.

Soundproofing

The inside of a case can be lined with 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

Heat sink

Large heat sinks designed to operate efficiently with little airflow are often used in quiet computers.

Fan

If they use fans at all, quiet PCs typically use larger-than-usual low-speed fans with quiet-running motors and bearings. The 120 mm size is common, and 140 mm fans are used where cases or heat sinks allow them. Quiet fan manufacturers include Nexus, EBM-Papst,

Bearing and motor noise is an important consideration. Soft mounting fans (e.g. with rubber or silicone fan isolators) can help reduce transfer of fan vibration to other components.[37]

Piezoelectric fans are often quieter than rotating fans and may consume less power.^[38][39] Intel, Murata, and others have recently done development on use of piezoelectric fans in desktop PCs.^{[citation needed]}

Watercooling

Watercooling^[40] is a method of heat-dissipation by transferring the heat through a conductive material which is in contact with a liquid, such as demineralised water with an additive to prevent bacterial growth. This water travels in a loop that usually contains a reservoir, radiator and pump. Modern 12 V DC pump technologies allow extremely powerful and quiet designs.

By efficiently transferring device heat to a separate heat exchanger that can use larger heat sinks or fans, watercooling can allow quieter overall operation. Devices such as

Secondary storage

Hard drive

Older hard drives used ball bearing motors but more recent desktop hard drives use quieter fluid bearing motors.^[42]

The smaller 2.5" form-factor hard drives generally vibrate less, are quieter, and use less power than traditional 3.5" drives,^[42][43] but often have lower performance and less capacity, and cost 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

Solid-state storage

A solid-state drive has no moving mechanical components and runs silently,^{[44][45][46][47]} but (as of 2016^[update]) are still roughly four times more expensive per unit of storage than consumer-grade HDDs.^[48]

In some cases, other solid state storage methods may be suitable:

• Compact Flash (CF) cards can be used as secondary storage. Because they use a slightly modified Parallel ATA (PATA) interface, a simple adapter is all that is needed to connect CF cards to function as an PATA or PC Card hard disk. CF cards are also small, allowing 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 GB and are only available in small capacities and there are also issues regarding the maximum number of writes to each sector.^[49]
• USB. They are based on flash memory, so have the same advantages and disadvantages as CF cards, except that speed is limited by the USB bus
  .
• 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.

All forms of solid-state storage are more expensive than traditional spinning-disk drives, so some quiet PC designs use them in conjunction with a secondary hard drive which is only accessed when needed, or with network-attached storage, where less-quiet traditional hard drives are kept remote.

Optical drive

Optical drives can be slowed down by software to quiet them, such as

In contrast to desktop PCs, laptops and notebooks typically do not have power supply fans or video card fans, generally use physically smaller hard drives and lower-power components. However, laptop CPU fans are usually smaller, so may not necessarily be quieter than their desktop counterparts - a smaller fan area requires faster fan speeds to move the same amount of air.^[50] Furthermore, limited space, limited access and proprietary components make silencing them more difficult.

Fanless

A number of laptops and netbooks however do not use cooling fans at all.^{[51][52][53][54][needs update]}

Fanless

• Keyboard computer

References

External links

The Wikibook How To Assemble A Desktop PC has a page on the topic of: Silencing

• Silent PC Review – articles on various aspects of PC acoustics.
  • What is a "Silent" Computer?, Silent PC Review, 21 September 2006.
  • What is a "Silent" Computer? (in Dutch), Vrad.
  • Reference/Recommended, Silent PC Review.
  • In a nutshell, Silent PC Review.
• PC, SE: Silent.