A computer case, also known as a computer chassis, is the

enclosure Enclosure or inclosure is a term, used in English landownership, that refers to the appropriation of "waste" or "common land", enclosing it, and by doing so depriving commoners of their traditional rights of access and usage. Agreements to enc ...

that contains most of the hardware of a

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

. The components housed inside the case (such as the CPU,

motherboard A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see #Nomenclature, "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It ho ...

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...

mass storage In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. In general, the term ''mass'' in ''mass storage'' is used to mean ''large'' in relation to contemporaneous hard disk drive ...

devices, power supply unit and various

expansion card In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus sl ...

s) are referred as the ''internal'' hardware, while hardware outside the case (typically

cable Cable may refer to: Mechanical * Nautical cable, an assembly of three or more ropes woven against the weave of the ropes, rendering it virtually waterproof * Wire rope, a type of rope that consists of several strands of metal wire laid into a hel ...

-linked or plug-and-play devices such as the display, speakers, keyboard,

mouse A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...

and

USB flash drive A flash drive (also thumb drive, memory stick, and pen drive/pendrive) is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and u ...

s) are known as ''

peripheral A peripheral device, or simply peripheral, is an auxiliary hardware device that a computer uses to transfer information externally. A peripheral is a hardware component that is accessible to and controlled by a computer but is not a core compo ...

s''. Conventional computer cases are fully enclosed, with small holes (mostly in the back panel) that allow

ventilation Ventilation may refer to: * Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation ** Mechanical ventilation, in medicine, using artificial methods to assist breathing *** Respirator, a ma ...

and cutout openings that provide access to plugs/sockets (back) and

removable media In computing, a removable media is a data storage media that is designed to be readily inserted and removed from a system. Most early removable media, such as floppy disks and optical discs, require a dedicated read/write device (i.e. a drive) ...

drive bay A drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed. Over the years since the introduction of the IBM PC, it and its compatibles have had many form f ...

s (front). The structural frame ( chassis) of a case is usually constructed from rigid

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

s such as

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

(often SECC — steel, electrogalvanized, cold-rolled, coil) and aluminium alloy, with hardpoints and through holes for mounting internal hardware, case fans/ coolers and for organizing cable management. The external case panels, at least one of which are removable, cover the chassis from the front, sides and top to shield the internal components from physical intrusion and

dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...

collection, and are typically made from painted metallic and/or

plastic Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding ...

material, while other materials such as mesh,

tempered glass Tempered or toughened glass is a type of safety glass processed by controlled heat treatment, thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into Compression (physics), comp ...

, acrylic,

wood Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...

and even Lego bricks have appeared in many modern commercial or home-built cases. In recent years, ''open frame'' or ''open air'' cases that are only partly enclosed (with freer ventilation and thus theoretically better

cooling Cooling is removal of heat, usually resulting in a lower temperature and/or Phase transition, phase change. Temperature lowering achieved by any other means may also be called cooling. The Heat transfer, transfer of Internal energy, thermal energ ...

) have become available in the premium gaming PC market.

Sizes and terminology

Cases can come in many different sizes and shapes, which are usually determined by the form factor of the

since it is physically the largest hardware component in most computers. Consequently, personal computer form factors typically specify only the ''internal'' dimensions and layout of the case. Form factors for rack-mounted and blade servers may include precise ''external'' dimensions as well since these cases must themselves fit in specific enclosures. For example, a case designed for an

ATX ATX (Advanced Technology Extended) is a motherboard and power supply configuration specification, patented by David Dent in 1995 at Intel, to improve on previous de facto standard, ''de facto'' standards like the AT (form factor), AT design. ...

motherboard and power supply unit (PSU) may take on several external forms such as a vertical ''tower'' (designed to sit on the floor, height > width), a flat ''desktop'' (height < width) or '' pizza box'' (height ≤ ) designed to sit on the desk under the computer's monitor). Full-size tower cases are typically larger in volume than desktop cases, with more room for

expansion slot Expansion may refer to: Arts, entertainment and media * ''L'Expansion'', a French monthly business magazine * Expansion (album), ''Expansion'' (album), by American jazz pianist Dave Burrell, released in 2004 * Expansions (McCoy Tyner album), ''Ex ...

s, and custom or all-in-one (AIO) water cooling solutions. Desktop cases—and ''mini-tower'' cases under about high—are popular in business environments where space is at a premium. Stripped-computer-case

Currently, the most popular form factor for desktop computers is ATX, although microATX and small form factors have also become very popular for a variety of uses. In the high-end segment, the unofficial and loosely defined XL-ATX specification appeared around 2009. It extends the length of the mainboard to accommodate four graphics cards with dual-slot coolers. Some XL-ATX mainboards increase the mainboard's width as well, to allow more space for the CPU, Memory PWM, and in some cases, a second CPU socket. While the market share of these exotic high-end mainboards is very low, almost all high-end cases and many mainstream cases support XL-ATX (10 expansion slots). As of 2018, no major motherboard manufacturer has made an XL-ATX board for several years. E-ATX is similar to XL-ATX in that it is larger than ATX and is also loosely defined. Unlike XL-ATX, E-ATX motherboards and cases are still in production (as of 2020), and support quad-channel memory across 8 slots of ram, up to 4 PCI-e expansion slots for up to 4 double slot graphics cards and a single CPU such as the AMD Ryzen Threadripper 3990X. Companies like In Win Development, Shuttle Inc. and AOpen originally popularized small cases, for which FlexATX was the most common motherboard size. As of 2010

Mini ITX Mini-ITX is a motherboard form factor developed by VIA Technologies in 2001. Mini-ITX motherboards have been traditionally used in small-configured computer systems. Originally, Mini-ITX was a niche standard designed for fanless cooling with ...

has widely replaced FlexATX as the most common small form factor mainboard standard. The latest mini ITX mainboards from Asus,

Gigabyte The gigabyte () is a multiple of the unit byte for digital information. The SI prefix, prefix ''giga-, giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte i ...

, MSI, ASRock, Zotac and

Foxconn Hon Hai Precision Industry Co., Ltd. (), Trade name, doing business as Hon Hai Technology Group () in Taiwan, Foxconn Technology Group () in China, and Foxconn () internationally, is a Taiwanese multinational corporation, multinational electron ...

offer the same feature set as full size mainboards. High-end mini ITX mainboards support standard desktop CPUs, use standard memory DIMM sockets, and mostly feature a full-size PCI-E 16× slot with support for the fastest graphics cards, although some instead use a PCI, or PCIe slot of fewer than 16 lanes. This allows customers to build a fully-fledged high-end computer in a significantly smaller case. Apple Inc. has also produced the

Mac Mini Mac Mini (stylized as Mac mini) is a small form factor (desktop and motherboard), small form factor desktop computer developed and marketed by Apple Inc. It is one of the company's four current Mac (computer), Mac desktop computers, positioned ...

computer, which is similar in size to a standard CD-ROM drive, and many manufacturers offer mini-ITX cases of similar size for low-wattage CPUs with integrated graphics. Tower cases are often categorized as mini-tower, midi-tower, mid-tower, or full-tower. The terms are subjective and inconsistently defined by different manufacturers. ''Full tower cases'' are typically or more in height and intended to stand on the floor. They can have anywhere from six to ten externally accessible drive bays. These cases were originally developed to house

file server In computing, a file server (or fileserver) is a computer attached to a network that provides a location for shared disk access, i.e. storage of computer files (such as text, image, sound, video) that can be accessed by workstations within a co ...

s which would typically be tasked with serving data from expensive CD-ROM databases that held more data than the hard drives commonly available at the time. Hence, many full tower cases include locking doors and other physical security features to prevent theft of the discs. However, as computing technology moves from

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...

s and

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains computer data storage, data computers can read, but not write or erase. Some CDs, called enhanced CDs, hold b ...

s to large capacity hard drives, USB flash drives, and network-based solutions, more recent full tower cases typically only have none, one, or two external bays for CD drives, with the internal bays moved elsewhere in the case to improve airflow. Today, full tower cases are commonly used by enthusiasts as showpiece display cases with custom water cooling, lighting, and tempered glass (replacing acrylic). They may also hold two computers (as is the case with the Corsair 1000D) and dual power supplies (Corsair 900D). ''Mid-tower cases'' are smaller, about high with two to four external bays. They may also hold two computers. A ''mini-tower'' case will typically have only one or two external bays. The marketing term ''midi-tower'' sometimes refers to cases smaller than mid-tower but larger than mini-tower, typically with two to three external bays. Other times the term may be synonymous with ''mid-tower''.

Layout

Computer cases usually include sheet metal enclosures for a power supply unit and drive bays, as well as a rear panel that can accommodate

connectors protruding from the motherboard and

s. Most cases also have a power button or switch, a reset button, and LEDs to indicate power, hard drive activity, and network activity in some models. Some cases include built-in I/O ports (such as

USB Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

and headphone ports) on the front of the case. Such a case will also (normally) include the wires needed to connect these ports, switches, and indicators to the motherboard.

Major component locations

* The

is usually screwed to the case along its largest face, which could be the bottom or the side of the case depending on its form factor and orientation. * Form factors such as

provide a back panel with cut-out holes to expose I/O ports provided by integrated peripherals, as well as

s which may optionally expose additional ports provided by

s. Many larger ATX cases can also be used with motherboards of other form factors. * The power supply unit mounting point differs from case to case, but the most commonly used locations (both at the rear of the case) and their advantages/disadvantages are: **The top of the case, usually allowing the PSU's built-in fan to act as an auxiliary exhaust fan but causes the PSU to be fed air heated by the internal components of the case, thus causing PSU efficiency and lifespan degradation. **The bottom of the case, with an (often filtered) vent in the bottom of the case allowing the PSU to draw cool air from the outside. *Regardless of the mounting position, the PSU will usually be attached to the case with four

screw A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the screw head, head. The most common uses of screws are to hold objects together and there are many forms for a variety ...

s to support its weight. * Most cases include

s on the front of the case; a typical ATX case includes 5.25", 3.5" and 2.5" bays. In modern computers, the 5.25" bays are used for

optical drive In computing, an optical disc drive (ODD) is a disk drive, disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs. Some driv ...

s, the 3.5" bays are used for

hard drive A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, pla ...

s and card readers, and the 2.5" bays are used for solid-state drives. * Buttons and LEDs are typically located on the front of the case; some cases include additional I/O ports, temperature, and processor speed monitors in the same area. * Vents are often found on the front, back, top, left side panel, and sometimes on the right-side panel of the case. Regardless of their placement, their purpose is either to let cool air into the case or to let hot air out. Larger vents usually allow cooling fans to be mounted via surrounding threaded screw holes. Newer cases include mountings for larger 120 mm or 140 mm cooling fans for quieter operation than the 80 mm fans formerly common. * An I/O template, or I/O plate, fits around the motherboard's back panel of external ports. Sometimes provided by the case manufacturer, it is often replaced by the one that comes with the motherboard.

Internal access

Accessing the interior components of a modern

tower case is done by removing the side panels. Looking front-to-back, accessing the motherboard, PSU, drive bays, and most case fan installation points are done by removing the left side panel. Removing the right-side panel is done less often to access the space behind the motherboard mounting plate. This space is devoted to cable management, as cables routed in front of the motherboard may disrupt the flow of air within the case causing increased temperatures. BTX, an uncontemporary standard, has the main side panel on the right side as opposed to the left. Some upside-down designed ATX cases are also accessed by removing the right-side panel door. Alternatively, the case may have a single large U-shaped cover that saddles the chassis. This was ubiquitous in AT tower cases. To prevent the buildup of performance-degrading dust within the case, many models feature dust filters in front of the air intake fans. While the exact method of accessing the front filters depends on the case model, it usually requires the removal of the entire front panel. Removal of the front panel itself may or may not require the removal of one or both of the side panels. If there is any doubt, consult the user's manual if possible. Traditionally, most computer cases required computer case screws to hold components and panels in place (i.e. motherboard, PSU, drives, and expansion cards). From the early 2000s onwards there is a trend towards tool-less cases, in which components are held together with snap-in plastic rails, thumbscrews, and other methods that do not require tools; this facilitates quick assembly and modification of computer hardware and is also cheaper to manufacture.

Appearance

Throughout the 1990s, most computer cases had simple rectangular shapes, and were often painted beige or

white White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

with little attention given to the visual design. Beige box designs are still found on a large number of budget computers assembled from generic components. These class of machines are now known as white box computers, even though the cases for these types of machines are now generally colored black or silver instead of beige. More modern computer cases include a much wider range of variation in shape, color, form factor, and materials, such as brushed aluminium and/or tempered glass which are offered with more expensive cases. ''Case modding'' is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components. Since the early 2000s, some cases have included clear side panels or acrylic windows so that users can look inside while it is operating. Modded cases may also include colored internal lighting, custom paint, or liquid cooling systems. Some hobbyists build custom cases from raw materials like aluminum, steel, styrofoam, acrylic, or wood. Historically, cases used CCFL lighting and eventually single color LEDs as strips or in fans to illuminate their interior; modern cases use RGB LED lighting instead, often incorporated into case fans. To improve airflow while allowing RGB fans to be visible, many cases as of 2020 use metal meshes, without any external bays. Many include a PSU shroud and vertical gpu mounts. Some used to include holes to support external water cooling radiators. Cases with side windows may have side fans (on the window) as well, although it is uncommon for cases with glass windows to have side fans.

Case manufacturers

Prominent after-market case manufacturers include Antec
BitFenix
Cooler Master, Corsair, Fractal Design, In Win Development, Lian Li, NZXT Corp., Phanteks, Rosewill, and Thermaltake, (DIY PC)

Intrusion detection

Some computer cases include a biased switch ( push-button) which connects to the motherboard. When the case is opened, the switch position changes, and the system records this change. The system's

firmware In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, h ...

BIOS In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization d ...

may be configured to report this event the next time it is powered on. This physical intrusion detection system may help computer owners detect tampering with their computers. However, most such systems are quite simple in construction; a knowledgeable intruder can open the case or modify its contents without triggering the switch. In the past, many tower cases (including full tower cases) intended to house

s featured a locking door covering the external drive bays. This was a security feature intended to prevent the theft of the

discs the drives would be holding. At the time, CD-ROM capacity was larger than the hard disks available, and many business-critical databases were distributed on this media. These databases were often very expensive or held proprietary data, and hence would be likely targets for casual theft.

Gallery

ATX computer case - left - 2018-05-18.jpg, Interior of a 2018 ATX computer tower ATX computer case - back - 2018-03-18.jpg, Back of an ATX computer tower ATX computer case - right - 2018-05-12.jpg, Right part of an ATX computer case with the fixing of the CPU at top right ATX computer case - front - 2018-05-12.jpg, Front of an ATX computer case ATX computer case - facade buttons - 2018-05-12.jpg, Facade buttons of an ATX computer case Macpro.png, Mac Pro tower case. Note the two barely visible front intake fans. Modified-pc-case.png, Enthusiast case featuring translucent panel casemod SWTPC6800 open.jpg, SWTPC 6800 case with SS-50 and SS-30 buses—an early hobbyist machine Paris servers DSC00190.jpg, Three of the Wikimedia servers in 1U rackmount cases Home theater PC front with keyboard.jpg, Antec Fusion V2 home theater PC case with VFD display, volume control and some

ports Ports collections (or ports trees, or just ports) are the sets of makefiles and Patch (Unix), patches provided by the BSD-based operating systems, FreeBSD, NetBSD, and OpenBSD, as a simple method of installing software or creating binary packages. T ...

on front 80486-Desktop-PC.jpg, 8-slot Baby AT form factor case Power Macintosh 9600 350.jpg, Power Mac tower case NeXTcube.jpg, NeXT Cube SGI-indigo-front.jpg, SGI Indigo tower case Silicon Graphics O2 Plus.jpg, SGI O2 tower case IBM PC 5150 no monitor.jpg, IBM Personal Computer IBM 5150 Casing.jpg, IBM Personal Computer 5150 bare 5-slot case IBM PC XT color.jpg, IBM Personal Computer XT IBM PS2 MCA Model 55 SX, front.jpg, IBM PS/2 Model 55 SX IBM PS2 MCA Model 55 SX, internal components overview.jpg, IBM PS/2 Model 55 SX Mac mini mid2010 front.jpg, The 2010

from

Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

References

External links

Chassis Form Factors
{{Basic computer components