Types and types of computer cases: all characteristics and descriptions. What are the types of system units? Types of system enclosures
The case is not only the appearance of the PC, but also its protection, addition, and integral part. The system case is the main element of the computer system on which all its devices are mounted. Therefore, you need to choose a computer case with knowledge of their types and functionality. So what is the difference between the “external shells” of a PC and what tips can you give for choosing a computer case?
Housings can have different shapes - vertical and horizontal.
Vertical– tower ( tower) is usually located next to the monitor or placed under the table down. Vertical towers are divided into the following formats: mini-tower, midi-tower, big-tower.
Mini-tower - the body is quite low in height. At first, during the era of the dominance of Baby AT format motherboards, it was the most widespread, but today it is much less common, because problems may arise with placing full-size ATX motherboards in it; only small-sized boards in micro-ATX and flex-ATX formats remain. Such cases are most often used in computers of the simplest configurations and are used as office machines or network terminals.
Midi-tower – the most common case format today is midi (middle)-tower ATX. It allows the use of a large number of drives and almost all types of motherboards with acceptable overall dimensions. This type of case is suitable for almost all home and office machines and is used everywhere.
Big-tower – are the largest cases and provide the placement of motherboards of any size and the largest number of devices in the 5.25" format, most often 4 - 6. In addition, they are most often equipped with high-power power supplies. The main area of application of such cases is workstations, small servers and computers for advanced users.
Horizontal the form is called “desktop” ( desktop). Usually located under the monitor. This design looks very elegant. However, assembling and repairing a desktop-based computer is difficult and inconvenient. In addition, the volume of the horizontal case is much smaller, and the power supplies are characterized by low power.
Speaking about the internal structure of the case, it should be said that cases are divided into form factors: ATX and BTX and their subtypes.
Form factor ATX
ATX (from English Advanced Technology Extended) is the form factor of the vast majority of modern (2005-2008) personal desktop computers.
ATX is the most modern case and most current motherboards are designed specifically for it. ATX is characterized by easier access to the internal devices of the computer (even without using a screwdriver). It also features improved ventilation inside the case, the ability to install more full-size expansion cards, and expanded power management capabilities.
ATX was created by Intel in 1995 and replaced the AT form factor that had been used for a long time (the real displacement of the previous standard occurred in late 1999 - early 2001). Other modern standards (microATX, flexATX, mini-ITX) usually retain the main features of ATX, changing only the size of the board and the number of expansion slots.
ATX defines the following characteristics:
- geometric dimensions of motherboards
- general requirements for the position of connectors and holes on the housing
- position of the power supply in the case
- geometric dimensions of the power supply
- electrical characteristics of the power supply
- the shape and position of a number of connectors (mainly power)
Dimensions of ATX form factor boards - 3 0.5x24.4 cm.
Dimensions of reduced versions of ATX motherboards:
Mini-ATX - 28.4x20.8 cm
Micro-ATX - 24.4x24.4 cm
Flex-ATX - 22.9x20.3 cm
Basic differences from the AT form factor
The processor's power is controlled by the motherboard; to ensure the operation of the control unit and some peripheral devices, even when turned off, a voltage of 5 volts is supplied to the board. (To provide electrical isolation, many ATX power supplies have a disconnect switch on the case.)
The power connector has changed: the previous standard (AT) used two similar power connectors, which could be mistakenly mixed up (although there is a rule - the four black wires (common) should be located next to each other), in the ATX standard the connector has an unambiguous inclusion.
The rear panel has changed; in the AT standard, on the rear panel there was only a keyboard connector and holes for expansion slots (or “plugs” with connectors connected to the motherboard via flexible cables); in the ATX standard there is a fixed-sized rectangular hole on the rear panel.
Inside this hole, the motherboard manufacturer can arrange the connectors in any order; the motherboard comes complete with an “IO plate” with slots for the connectors of a specific motherboard (this allows you to use the same case for motherboards with completely different sets of connectors).
The connection of the keyboard and mouse was standardized; the AT standard used a very large 5-pin DIN connector for the keyboard; there was no standard connector for the mouse; The ATX standard uses two PS/2 connectors.
MicroATX form factor (µATX, mATX, uATX)
MicroATX (µATX, mATX, uATX) - motherboard form factor 9.6x9.6" ( 24.4x24.4 cm), developed by Intel in 1997. Used only for x86 architecture processors.
The form factor was designed to be fully electrically and backwards mechanically compatible with the ATX form factor. µATX motherboards can be used in ATX cases (but not vice versa). When motherboards are released, motherboards in both ATX and µATX formats are often released on the same chipset, with the difference usually being in the number of PCI slots and integrated peripherals. Quite often the following difference is made: µATX boards are produced with a built-in video card, ATX - without (µATX is intended for office work and is not designed for gaming applications that require powerful video cards).
Mini-ITX form factor (µITX, mITX)
Mini-ITX is a form factor for motherboards developed by VIA Technologies. While maintaining electrical and mechanical compatibility with the ATX form factor, mini-ITX motherboards are significantly smaller in size ( 17 by 17 cm).
In 2001, the ITX form factor (21.5 x 19.1 cm) was created to promote the C3 processor (bought by Cyrix). In practice, it was not used; instead, a “reduced” form factor began to be actively used - mini-ITX .
One of the features of mini-ITX motherboards is the presence of a soldered processor, which reduces the overall cost of the computer. Due to the relatively low heat dissipation, many mini-ITX motherboards use a passive cooling system. In combination with SSD drives, this allows you to create silent computers that do not contain moving mechanical parts.
Due to their size, mini-ITX motherboards are used in embedded computers, thin clients, and undemanding home computers.
In 2005, VIA introduced a smaller version of mini-ITX called nano-ITX (12 x 12 cm).
Currently, most motherboard manufacturers have announced their mini-ITX form factor solutions, and computer developers can choose solutions on various architectural platforms: VIA, AMD, Intel. Such a wide choice makes it possible to build small-sized, cost-effective systems to perform a wide variety of tasks, from embedded control systems, payment terminals, to multimedia centers. The relatively low performance of Mini-ITX platforms, associated with their reduced heat dissipation, makes these solutions ideal for use in NAS and SAN network drives, as well as in home mini-servers.
Form factor BTX
BTX (Balanced Technology Extended) is a form factor proposed by Intel in 2005. It was assumed that BTX would replace the ATX form factor.
The format was proposed at the end of 2004 - beginning of 2005 by Intel (the author of the ATX standard), but it turned out to be not very popular, so at the beginning of 2006, most desktop computers (according to froogle) were sold with the ATX or microATX form factor. The first BTX form factor computer was sold by Gateway Inc. Dell also produced computers in this form factor.
However, the ever-increasing heat dissipation of Pentium 4 processors, which was the main reason for the creation of BTX, forced Intel to move to other ways of increasing power, and the Intel Core generation was already much more energy efficient and cooler. Thus, the main advantage of BTX became insignificant, and doubts arose about the advisability of its further support.
In September 2006, Intel abandoned support for the BTX standard.
Main advantages:
- Reducing the height of the motherboard with a processor cooler installed, reducing the height of the IO Plate.
- ensuring cooling of all computer components (taking into account not only the heating from the processor, but very hot video cards, hard drives) by creating direct air currents inside the case. To do this, the motherboard is installed vertically on the left wall of the case (in ATX - on the right), due to which the peripheral cards are positioned upward with the radiators. This arrangement promotes air exchange.
- reduction of noise level.
Form factor eATX (EATX)
Form factor eATX (EATX) - (English Extended ATX) differs from ATX mainly in size. This standard allows the installation of motherboards up to 30.48x33.02 cm in size. Most EATX cases can also install ATX motherboards.
system case
The computer case is of great importance for the stable and quiet operation of your home computer. Although many believe that the case is not the main element of the system unit and is needed for fastenings inside its components. In fact, this is not so; the case is an important element that ensures the placement and rigid fixation of all its devices, and protection from environmental influences.
The most important thing for a system unit case is its dimensions. There are several standard sizes of computer cases: Barebone, Slim, MiniTower, MidiTower, FullTower and BigTower (from Tower - tower), and the same number of form factors: AT, ATX, E-ATX, mATX, miniITX, XL-ATX. All of them are interconnected by overall dimensions. For example: a Big-Tower case has an XL-ATX form factor with case dimensions of about 234 x 600 x 555 mm, and a small Mini-Tower has an mATX form factor with dimensions of 181 x 363 x 400 mm (width x length x height).
Horizontal
There is another type of horizontal system unit, the so-called desktops. The time for desktop cases is already passing. 
Translated, desktop means desktop, which speaks for itself and is still used in offices in order to save work space. Such system units have relatively small overall dimensions, and the horizontal arrangement allows you to place a monitor on it. With the advent of LCD monitors, the dimensions of which are much smaller, interest in these types of system unit housings has arisen again. Their typical dimensions are 450 × 450 × 200.
Vertical
We will no longer consider the horizontal system unit and will focus on the more popular types of system unit cases - “towers”. 
The Barebone system case is suitable for space connoisseurs; it takes up very little space. In addition, such a case looks great. As a rule, such cases are not sold separately; they come with pre-installed components. Such systems often use so-called passive cooling methods. 
The AT housing standard is practically not used at the moment. Used for assembling computers based on Intel 486, Pentium I, Pentium II and their modifications.
Extremely integrated Flex-ATX motherboards and their continuation - Slim cases. In general, the buildings are cramped and extremely uncomfortable, but on the other hand, outwardly they look very original.
Small-height mini-tower cases used to be the most widespread, but now they are much less common, since placing full-size ATX motherboards in them can cause problems, leaving only small-sized motherboards in micro-ATX and flex-ATX formats. Such cases are most often used in PCs of the simplest configurations and are used as office machines or network terminals.
Today, the most common case format is midi tower ATX, which allows the use of a large number of drives and almost all types of motherboards with acceptable overall dimensions. Being a real “workhorse”, optimally suited for solving the widest range of tasks, this type of enclosure is used almost everywhere.
The big tower has the largest dimensions of the case. They provide accommodation for motherboards of any size and the largest number of 5.25″ format devices, most often 6. In addition, they are usually equipped with high-power power supplies. The main areas of application for cases are workstations, small servers and computers for advanced users.
Quality
The convenience of working with it and safety depend on how the body panels, inserts, etc. are made. Metal corners should be smoothed so that it is impossible to scratch your hands on them. Also, the body must be sufficiently rigid. Of course, all painted body panels must be well finished. It is also worth paying attention to the material of manufacture – iron or aluminum. Aluminum, of course, is preferable, but the prices for aluminum cases are noticeably higher than for iron ones.
Internal layout
For components inside the system unit, there must be enough space and opportunity to improve the computer. The amount of heat generated by modern components requires an appropriate size, so the system unit inside must have enough space for ventilation. The dimensions of computers purchased for offices can be any size.
Let's look at the photo of the system unit inside. Here you can see that a midi tower case is used for the system unit, quite spacious in height and width, this can be seen from the installed vertical cooler. The motherboard is mATX format, it is possible to install a full-size board. The power supply has a 120 mm cooler. There is space for installing an additional fan on the back wall, and there are also ones on the side cover. This shows that this system unit has the possibility of upgrading and organizing high-quality cooling.
Case functionality
Pay attention to the location of buttons and switches, as well as the front USB connectors and audio connectors. Try them on right away to see if they are comfortable for you to use. It is also worth paying attention to whether the case provides the possibility of screwless assembly of components. Screwless assembly implies a large number of fasteners and latches for equipment, so when assembling the system unit you do not have to use screws and a screwdriver, which is very convenient.
Ease of access inside. Removable side panel (left side when viewed from the face) provides easy access to internal components. Most cases have both sides removable. Previously, the U-shaped casing was traditional. For quick removal (of casing or wall) there are snap locks instead of traditional screws. This allows you to do without a screwdriver at all.
On the front side there are 2 control buttons: power on (POWER) and reboot (RESET). It’s bad if they are all the same, for example, round, the same diameter and color, and located close to each other.
Manufacturer
There are many manufacturers - from little-known Chinese companies to well-known companies (Thermaltake). You understand, it is better to have a system unit with a case from a well-known brand, since it implies the quality of manufacture and use at the proper level.
Price
The range is very wide - from 100 to... several thousand. A cheap system unit case may have flaws, such as: weak design, poorly thought-out cooling inside, inconvenience of working inside the case, using buttons and connectors.
When choosing a case, the most important criterion is its form factor: what dimensions it has and what motherboards can be installed in it. For standard computers located under a desk, ATX MidiTower cases that are half a meter high are best suited. If you plan to place the PC directly on the table, a compact Mini-ITX case is suitable for you.
Power supply location
As a rule, in MidiTower cases, the power supply is located on top of the rear panel - it takes air from the case and exhausts it back. Performing such a dual function - power supply and ventilation of the case - leads to the fact that the electronic components of the power supply, being exposed to warm air from the case, are poorly cooled, which is why their service life is reduced.
From a heat transfer point of view, a better case option is when the power supply is located at the bottom of the case: It draws fresh cooling air from below through a dust filter, and the case fan exhausts air heated by the CPU and GPU through the top of the rear panel. The location of the power supply at the bottom is not suitable only if the PC will be placed on a soft, long-pile carpet.
If you are building a home computer with a long service life in mind, we do not recommend purchasing a case with a pre-installed power supply. It is better to separately purchase a power supply unit that will meet your requirements. You can read more about choosing power supplies in our material.
Quality and cooling system
Simple “boxes” cost up to 2,000 rubles, but a bad choice can literally cause you pain: the edges of cases from little-known manufacturers are usually sharp, and it is very easy to scratch your fingers or palm during assembly.
It should be added to this that thin metal bends easily, and some components can only be installed using remarkable strength or ingenuity. But in the end, the computer will still vibrate and rattle, which will accelerate the wear of components.
Our recommendation for "Best Value" - Case Sharkoon VS4-S. It is also made of thin metal sheet: this can be determined by its technical characteristics - it weighs only 3.5 kg. True, the dangerous edges have been smoothed out, and the design gives the impression of being quite stable.
Expensive cases of common brands are made of durable material: Antec, BitFenix, Chieftec, Cooler Master, Cooltek, Corsair, Enermax, Fractal Design, Lian Li, Thermaltake. This can also be immediately determined by weight of 8 kg or more. Such cases, costing from 5,000 rubles, are made much more carefully, and the side covers are fixed not only with screws, but also with a shutter mechanism.
The case should embody the functionality that is important to you, including the presence of front USB connectors and the number of drive bays. When choosing a case, the space for the video card is also important.
Often, mid- and high-class cases are equipped with special soundproofing gaskets on the front, top, and sides, so they are locked hermetically. In addition, they can install additional fans or a liquid cooling system.
Another important point is the mounting of hard drives. When operating, HDDs vibrate and make noise, which in simple “boxes” turns into an annoying hum. In good cases, hard drives are separated from structural elements by vibration-isolating rubber gaskets and washers. All these advantages are embodied in the body Fractal Design Define R5.
Mini-ITX for small dimensions
Mini-ITX form factor cases should be selected based on functionality, design, and size. There are options in the form of cubes (Cube), in which the motherboard is built horizontally, and above it there is enough space for drives and a video card. In other desktop cases, the motherboard is also positioned horizontally, only the case itself is lower.
The most compact cases - Small Form Factor - are designed only for the width of the motherboard. And they are powered by external power supplies, like in laptops. It's best to choose a manufacturer that offers a variety of different ITX cases. At a price of 5,000 rubles for the case along with the power supply, you should not expect high quality in this category– it is by no means easier to produce compact cases than large ones, and their small quantity justifies high prices.
Photo: Juliane Weber; manufacturing companies
To make the right decision and understand which computer case is best to choose, you need to answer yourself a few questions. This determines which criteria are important to consider first, which are of secondary importance, and which can be neglected.
Are the dimensions of the system unit important?
Which computer case is better to choose?in size, directly depends on the location of the system unit. If it stands somewhere under the table or in the corner of the room on a separate bedside table, then the dimensions can be ignored. A spacious “box” is the key to good ventilation, effective cooling and easy maintenance.
If the PC will stand on a table, and a very large size is clearly undesirable, then you should look towards mATX, Mini-Tower or Mini-ITX cases. In such system units there is enough space to accommodate a corresponding (Mini, Micro, Flex-ATX or ITX) motherboard with other components. But it will not be possible to install a full-fledged ATX motherboard in them.
Does design matter?
If the computer is planned to be pushed deeper under the table and forgotten, leaving it as a “freelance dust collector,” then few people care about its appearance. In this case, beforehow to choose a PC case,You don’t have to think about the exterior at all. It works - OK, doesn't overheat - great, doesn't make noise - absolutely lovely. The main thing is that it does not suck up dust, since it is located deep under the table. Otherwise, within a year or two, the radiator will get filled with such “felt boots” that you can even make rifle wads out of it, and “hello, overheating.” But more about dust below.
If the computer is in a visible place, and it is not just an office “box” with basic filling, but a powerful gaming machine, you want the appearance to indicate this. Then spending a hundred thousand rubles won’t be such a pity. In this case, you want to buy an unusual case with transparent windows, multi-colored LEDs on the fans, a front lid and other amenities. Here the choice is a matter of taste; the main thing is that you don’t have to sacrifice functionality for the sake of beauty.
Is high-quality cooling required?
Which computer case to choose– depends on the heat dissipation of components. Modern budget processors from the Intel Pentium and Celeron families are characterized by low power consumption and, as a result, heating. Any compact case is enough for them; the hardware in it will not “suffocate”. And if PCI and PCI-Express devices (video card, sound card, TV tuner, video capture card, etc.) are not needed, you don’t have to worry about cooling. 
In the case of a gaming PC, consisting of a powerful processor, a powerful video card, and a couple of tens of gigabytes of RAM, more attention should be paid to cooling. Compact ITX and MicroATX cases are not suitable for them: the parts inside will be too cramped. In addition, not a single powerful gaming video card will fit into a narrow-profile system unit. If there are two graphic cards, you have to forget about compactness altogether.
There is a myth that for a powerful gaming PC, a bottom-mounted power supply is preferable. In fact, there is no practical difference in cooling efficiency. The only component that will benefit from this is the power supply itself, which will have to pull less hot air out. All examples of how a case with a bottom-mounted power supply shows lower temperatures are not due to the advantages of the layout, but to the dimensions. After all, as a rule, such cases are characterized by increased dimensions. And low-block cases are more expensive, which means engineers are more concerned about optimizing the air flow inside. 
The grilles that people like to equip cases with on all sides are also not a definite plus. Cooling efficiency does not depend on the number of holes, but on the air flow inside the case. Excessive perforation can even cause harm, since it collects dust inside much faster.
Do I need a built-in power supply?
Many computer cases come with a power supply. This practice is especially common in the budget segment, where buyers of devices seek to save money. After all, buying a case with a power supply for 3 thousand rubles is very attractive, especially considering the fact that the power supply itself of such power costs from 2 thousand. But in practice, “no-name” power supplies, supplied with cases and labeled as 400 or 500 W, barely live up to the characteristics on the label. At best, when operating at such power, it causes voltage drops along the most loaded lines. At worst, reaching peak consumption leads to PC shutdowns or even failure of the power supply (and with it a couple of other pieces of hardware) to fail.
You should only buy a case with a power supply if the computer is a low-power budget and/or office one. If the total consumption of components along the +12 V line is no more than 200-250 W, then the built-in power supply will be enough. But if your PC is gaming and consumes more than 300 W at 12 volts, you shouldn’t buy a case with a unit. After all, you will still have to buy a separate power supply, and the complete one will remain “dead weight”. 
The only exceptions are cases equipped with units Chieftek, FSP, Zalman, Cooler Master, Thermaltake, etc. These brands are of fairly high quality and the inscriptions on the labels are usually true.
Is the room dusty?
Dust is an insidious thing: to avoid it altogether, you need to thoroughly clean it every day, and also not keep objects that could potentially accumulate it. Upholstered furniture with fabric upholstery, blankets and pillows, carpets - all this collects small particles. Therefore, a computer installed in the bedroom will attract dust anyway. Even cleaning every few days will not completely get rid of it. And then powerful fans will collect dust inside the system unit, pulling it out from surrounding objects and air. 
In such a situation, abundant perforation (discussed above) is evil. The only way to combat dust is to create excess pressure inside the case by installing blow-out coolers from all possible sides. But this method is not a panacea: you also need to get fresh air from somewhere, without it the PC will “suffocate”, that is, it will always heat up.
You can, of course, buy the most insulated case (without extra holes), but it is only suitable for a low-power PC. A productive gaming machine in a tightly closed case requires a cooling system for heat removal. At a minimum, powerful fans are needed to create directed air flow inside. But then such a computer will roar like a fighter jet on takeoff.
If the floor in the room is linoleum, tile, parquet, laminate or other uncoated hard material, there is no upholstered furniture or it is leather, and cleaning is done frequently, then you can take any building. In such conditions, the threat of dust clogging is much lower.
How many disks will be installed in the PC?
Which case to choose for your PC, directly depends on how many drives you plan to install in it. If this is the “HDD+SSD” tandem that has already become common practice, then any case will do. Even the smallest models are equipped with at least two drive bays. But for a home media center equipped with several capacious hard drives, not every small case is suitable. If there are more than 4 HDDs, you need to carefully look for a compatible case. 
Where should the buttons and USB ports be so that they are easy to reach?
The issue of the location of buttons and interface connectors on the front panel only seems insignificant. In fact, it depends on how convenient the use of these elements will be. If you plan to place the PC under the table, then too low buttons and USB sockets will force you to reach for them, bending down every time. If the system unit stands on the table, on the contrary, the elements at the top become inconvenient. The worst thing is when they are on the “roof”. 
For a PC located at the bottom, it is best if both buttons and USB ports are located at the top of the panel (where the CD drive was located in the era of “hoary antiquity” and the reign of Pentiums). It's not bad when they are on a corner or on the top cover (but only if there is enough space between it and the table). If you plan to frequently use buttons, USB ports and audio jacks on the front panel, then a cover on them is undesirable. 
For those who place the PC on a desk, a case with a bottom arrangement of all these elements is suitable. Then you won’t have to reach up and forward every time you need to insert a flash drive or connect headphones.
Which body material is preferable?
Before how to choose a computer case, it is worth deciding on the material of the case. The most common options are steel and aluminum. There are also models with plexiglass elements, but they still have a metal base.
The steel body is more practical and reliable, but heavier. The exception is the cheapest Chinese “nonames”, the material of which is not far from a tin can. Steel with a thickness of less than 0.5 mm is easily deformed. If the cover screws are unscrewed several times to disassemble or clean the PC, the threads will quickly stop holding them. Tightening it too tightly also breaks it, forcing you to select bolts with a larger diameter. 
Thick (about 1 mm or more) metal in cases is not common, but can be found on sale. Thick-walled models are recommended for those who can sometimes take their anger out on their PC. If at the most crucial moment the game freezes or crashes, the Internet is lost, the PC randomly reboots and you can’t resist the temptation to kick it - it’s better to take a durable case so that you don’t have to repair your computer later from the consequences of such aggression.
Aluminum is a lightweight and elegant metal, but not very practical. All the shortcomings of thin “Chinese foil” are inherent in it, to one degree or another. For scratches and deformations, sometimes it is not necessary to kick the system unit: it is enough to carelessly touch it with your foot or the leg of a chair. Therefore, it makes little sense to put an aluminum case underneath: it won’t look beautiful anyway, but it will fall into an unpresentable state faster. And aluminum costs significantly more than steel.
How often do you have to tinker with your computer?
To understand which computer case is better to choose, you also need to take into account how often it will be opened and moved. Upgrade connoisseurs who, out of sporting interest, often upgrade their PCs, install new parts and replace old ones, it is advisable to look at models with special fasteners. Then you won’t have to aim a screwdriver at small screws every time you need to remove or install a video card, hard drive, DVD/BD drive, fan, etc. 
Classic screws are cheaper and simpler, but you will have to tinker with them longer when assembling a PC. Screw-mounted cases are recommended for office and home PCs that are assembled once and for all.
Conclusion
To understand which case to choose for a PC and not make a mistake, you need to take into account the main and secondary criteria. Dimensions, design, materials, cooling efficiency, a good power supply, dust protection, the number of drive bays, types of mounts, and the location of elements on the front panel are important when selecting. Considering all these parameters, you can buy the best case for a specific situation.
A big fan of high-quality Chinese technology, a lover of clear screens. Supporter of healthy competition between producers. He closely follows news in the world of smartphones, processors, video cards and other hardware.
The case of the system unit of a desktop personal computer contains: a motherboard with expansion cards, storage drives and a power supply. The type, size and placement of the motherboard used, the minimum power of the power supply and the maximum number of installed drives depend on the type of system unit case. Mounting (installation) places, or compartments for drives can be of two types - with external and internal access. Access to drives mounted in mounting locations of the latter type can only be achieved with the system unit case cover open.
There are currently two standard sizes of drives in use: 5.25 inches wide (CD (DVD) drives, some hard drives) and 3.5 inches wide (disk drives, hard drives). The number, location and standard size of drive bays largely determine the consumer qualities of the computer case.
Horizontal housings include: desktop (desktop), small-footprint (low profile), slimline (thin, slim) And ultra superslimline (ultra-compact). The motherboard in these cases is also located horizontally. In housing type desktop usually two 5.25-inch and one or two 3.5-inch bays with external access.
Cases with a vertically positioned motherboard resemble a tower in appearance ( tower) and usually come in three varieties: mini-tower, midi-tower And big-tower, which usually differ from each other in the number of 5.25-inch bays with external access (2, 3, 4 or more), the dimensions and power of the installed power supply, and, therefore, the ability to install additional expansion cards and drives.
One of the most common cases for a personal computer is the case type mini-tower. It typically has two 5.25-inch and 3.5-inch bays with external access, two 3.5-inch bays with internal access, and contains a 200-230 watt power supply. A mini-tower case can accommodate a standard set of drives and expansion cards. The enclosure provides greater expansion options midi-tower(three 5.25 and two 3.5-inch external and three to four 3.5-inch internal bays, a more powerful power supply). Housing type big-tower used for network servers, contain one or more power supplies with a power of more than 300 watts and have the widest expansion capabilities. In housings like slim Usually a weak power supply is installed (90-100 watts), and there is no more than one internal and one external compartment, which makes upgrading a PC in such a case problematic.
As a rule, on the body of the system unit there are several buttons for controlling the computer ( Reset, Turbo), LED and digital indicators of operating modes ( Turbo, Power, HDD, frequency), keypad lock ( Lock), built-in speaker and power switch ( Power).
There are special cases for multimedia computers, equipped with stereo speakers and audio output controllers. For comfortable work, housings with low noise levels are available ( low-noise), which use power supplies with low-noise fans.
The type, internal dimensions of the case and the power supply used depend on the motherboard used.
Currently, there are several, usually incompatible, standard housing sizes - old standards AT(for housings type desktop And tower) And LPX(for housings type slim) and offered by the company Intel new standards ATX (desktop And tower) And NLX (slim). They differ both in the size and location of the motherboard, and in the voltage ratings generated by the power supplies. Almost all computers are based on processors Pentium II and above are made in designs ATX or NLX. For cases ATX characterized by easier access to the internal components of the computer (often without the use of a screwdriver), improved ventilation inside the case, the ability to install a larger number of full-size expansion cards, and expanded power management capabilities.
Table. System unit case sizes
