The motherboard of the computer, for what it is designed and what it looks like

Материнская плата компьютера, для чего она предназначена и как выглядит

The computer's motherboard is the foundation on which all the components of the system unit are built .

The role of the computer motherboard can not be overemphasized. After all, it depends on it whether you can expand the functionality of your PC in the future or not? Increase the amount of RAM , put a more efficient graphics card? Will the further extension ("upgrade") of the entire system allow the presence of additional, originally not used, slots and connectors? This is like the foundation of the house: you will not make it qualitatively and, in time, the design can collapse.

The motherboard is a multilayered "pie" of single-layer (single-sided or double-sided) printed circuit boards. Each of the layers and represents a separate fee. Layering, first of all, is needed to combat cross-talk and interference created by the signal lines (paths) of the board, close to each other located. To increase this distance and isolate the signal lines of one layer from another and invent all this "sandwich". Each layer is separated from each other by special liners made of fiberglass (adhesive) and after all this is pressed into a special furnace.

Graphically, the internal structure of the product can be represented approximately like this:

As a bonus, the overall mechanical strength of such a structure also increases. The number of individual layers in modern branded products can reach up to ten, or even more! After that, almost finished motherboard on both sides is covered with a dielectric protective varnish of the right color, dried, drilled in it necessary holes for fasteners, installation of connectors and other components, metal holes on the edges and the product is almost ready! Of course, after that you need to install the connectors and the entire element base of the electronic components, carry out their soldering, quality control, perform comprehensive testing under load, but this process is clearly shown in the video under the article, so I see no reason to describe it again.

Note: printed circuit board or PCP (Printed Circuit Board) is a dielectric plate on which electrically conductive tracks are chemically or mechanically formed. They can be formed as a classical method of etching them on the board, or using laser engraving technology.

Since we are primarily interested in high-quality motherboards of the computer, let's turn our attention to the full-size payment from the manufacturer "Asus". A large number of elements on it and expansion slots allow us to hope for a good upgrade perspective, and a high-quality component base and board layout - for a long period of its operation.

Let's, as usual, go through all the notation in order and find out what components the motherboard of the computer consists of:

  1. socket CPU (connector where the computer processor is installed)
  2. there are two slots for PCI Express graphics card (in expensive motherboards you can install two discrete video cards at the same time)
  3. four slots for DDR2 memory
  4. north bridge of the computer motherboard chipset
  5. south bridge of motherboard chipset
  6. Cooling system radiators for power circuits (power phases) of the processor
  7. four USB output (output to the back of the computer case )
  8. outputs of the built-in sound card
  9. floppy disk interface 3.5 (drive) FDC controller
  10. four SATA outlets for connecting hard drives
  11. three PCI slots for connection of additional expansion cards (TV tuner, network or sound card, video capture card, etc.)
  12. battery "BIOS"
  13. four-pin 12-volt power connector processor
  14. 24-pin connector for power supply and voltage supply to the motherboard
  15. two connectors for connecting hard drives or CD-DVD-ROMs of the old "IDE"
  16. the BIOS chip itself

Let's stop with you on the most important points that require individual comments. In the image, we clearly see the cooling system in the center, with copper tubes that are diverging from it. The central radiator covers the "northern" chip of the motherboard chipset. It includes such important components as an integrated graphics card , a memory controller and a system bus controller (now these elements are actively transferred to the CPU) and, of course, it supports the interface with the "southern" microcircuit.

The names "north" and "south" bridge denote only the geographic location of these elements relative to PCI slots (north - higher or south - lower). The chip of the southern "bridge" is also covered by a radiator. It usually contains a controller of the built-in network card of the computer, USB bus, integrated sound, is responsible for the PCI bus, various sensors on the board, etc.

Note: chipset (chipset) - a set of chips designed to work together to perform any tasks. The second name is a set of system logic.

Applicable to computers, the classic chipset on the motherboard consists of two large chips:

  • north bridge (Northbridge)
  • south bridge (Southbridge)

The north bridge connects (through integrated controllers) the CPU with high-performance devices located on the computer's motherboard (memory, video adapter). The South "bridge" is responsible for supporting more "slow" peripheral devices (USB, sound and network card, hard drives, various expansion cards, etc.)

Here, for example, looks like a set of system logic ("north" - the larger and "south" - smaller bridge) produced by the company "VIA".

A set of system logic A set of system logic

We move on. Under the numbers "6" (see the first photo of the article) on the motherboard we have two radiators that cool the processor power circuits. Elements located under the radiators (capacitors and transistors) prevent strong fluctuations in the supply voltage of the CPU when its load changes. The quality of their performance is one of the indicators of a good motherboard. Agree, if the work of the computer will be unstable simply because of poor-quality power supply - it will be insulting!

Separately note that the elemental base of power circuits on modern motherboards is quite diverse: it includes a PWM controller, voltage converters, transistors, resistors, chokes, capacitors, etc.

The photo below shows a typical multiphase power scheme of a modern processor:

For example, voltage converters are needed in order to feed on one or another element strictly necessary for its normal operation of power. One thing is that at the input of the converter from the power supply "comes" 12 volts, but not all elements are exactly twelve! Here converters and reduce it to the desired value and "give" to the final "consumer" (a specific chip, or another element).

I suggest in more detail to talk about what all these phases are needed for and how they work? I think that it is necessary to know! The VRM (Voltage Regulation Module) or VRD (Voltage Regulator Down) can act as a down converter. Especially do not focus on this, it will be enough if you remember these acronyms and will know what they are referring to.

As a rule, several MOSFETs are also included in the converter circuit. They are controlled by an electric field, so they are called "field" (field). The abbreviation MOS is derived from a "metal-oxide-semiconductor", in the English version: "metal-oxide-semiconductor field effect transistor" or abbreviated MOSFET. Therefore, you can find the name, like mosfet-transistors (in the people - "mosfety").

At the heart of power phase management on the motherboard of the computer, as a rule, is the PWM-controller. The abbreviation PWM also has its own meaning and it is "Pulse Wide Modulation" - pulse-width modulation, in Russian PWM. Therefore, such components are often called PWM controllers.

Here's how it might look:

The PWM controller "learns" about the required power for the processor at the moment, using a special 8-bit signal, which "tells" to him what voltage should be applied to the CPU at any given time.

In very old computers, all the voltage regulator circuits were single-phase, but over time (as the power consumed by the processors) they became inefficient and manufacturers had to use several phases to adjust the voltage applied to the CPU. Hence the concept of "multiphase" appeared. Four-phase power eight-phase, etc. ... Now there is, it seems, even 24-phase! :)

What is behind this concept? Let's try to figure it out! What is the main limitation of a single-phase regulator? First of all, at the maximum current that can be passed through the elements that form it: mospets, inductors (chokes), capacitors. Their limitation is about thirty amperes, while modern CPUs can consume more than a hundred amps! It is clear that with such "requests" one phase "boils" very quickly :) That's it to compensate for this limitation, on motherboards and began to use multiphase power.

When using a multiphase regulator, the total load current can be distributed over the N-number of individual phases, which in total will produce the desired (nominal) power! For example: with a six-phase supply for each of the six phases, there will be 30 amperes (remember the current limit), while in total all of our phases can "pass" as many as 180 amperes at a peak load!

Note: for Intel processors of the generation Core i7 with power consumption over 130 watts (even considering the overclocking capability), six-phase power is enough! All that more - from the crafty marketer :)

It should also be borne in mind that the element base does not stand still and instead of conventional electrolytic capacitors, so-called solid-state polymers, whose service life exceeds 50,000 hours, chokes with a ferrite core, etc., are now widely used. All this together, allows you to pass through them the maximum current is no longer 30, but 40 amperes. Therefore, such a six-phase circuit (circuit) of the processor's power can fully provide current to the processor about 240 amperes (power consumption over 200 watts)! What kind of home CPU does it consume except AMD? :)

The last thing I would like to add, now on the motherboards of computers often used such a thing as a dynamic switching phases of power. This means that as the need (the processor consumes more current), an increasing number of phases are included in the work, and when the load decreases, some of them are turned off. In theory, a weak CPU can be started only with one working phase. It's another matter, how long will it last? But to start in test mode, this method may well be useful!

So, back to our main material! If you try to schematically depict the location of all the main elements and connectors on the computer's motherboard, you will get something like this:

As you can see, everything starts with the CPU and further (via the system bus) - the data is transferred to all nodes of the computer.

Here is another (graphical) embodiment of this idea:

Motherboard layout Motherboard layout

Let's say a few words about the system bus of the board - FSB (Front Side Bus - front system bus). This is a high-speed interface between the processor and the north bridge of the motherboard chipset. The higher its frequency, the higher the data transfer rate and the speed of the whole system. The FSB frequency is measured in megahertz.

Note: what is the frequency, what values ​​can take and what measure you and I have discussed here in this article.

Directly to the system bus, only the CPU is connected, the other devices are connected to it via dedicated controllers that are integrated into the chip of the north bridge.

For the sake of justice it is worth noting that now there is a tendency to a high integration of main controllers and even entire devices (graphics accelerator) directly into the core of the CPU.

One of the first chipsets was transferred to the memory controller, which reduced the time delays that are unavoidable in the transmission of data and commands on the system bus. For example, in the processor based on "Intel LGA1156" were transferred almost all the main controllers, previously located on the motherboard. As a result, in fact, there is no FSB in it!

The developers of the company "AMD" use their proprietary technology to replace the system bus. It's called Hyper Transport. This development has already undergone several revisions and is successfully used not only in personal computers, but also in high-performance devices such as Cisco's network routers.

Another of the "candidates" for transfer directly to the CPU core was embedded video, which used to feel quite comfortable in the north bridge of the motherboard chipset. And, it seemed, where could it get to from there ?! And some time passed and - please: a video core on one chip with a processor. Fantastic! :)

How did this become possible? First of all, due to the fact that the manufacturing process of all the main elements of the computer is constantly decreasing. For example, the processor family Intel Core i7 is made using 22 nanometer process technology, which allowed to place on the same area of ​​the crystal about 1.4 billion transistors!

Note: 22 nanometers correspond, in this case, to the linear resolution of the lithographic equipment used in the manufacture of the final device. And "nanometer" (nm or nm) is one billionth of a meter (millimicron)!

What do we have? With the decrease in the process technology, the size of the main elements (transistors) that we can place on the chip also decreases. Consequently, these same transistors in the same area we can accommodate more! And, as a result, build on their basis a built-in graphics engine or any other element in the CPU. Actually, developers are actively using it, trying to constantly reduce the technological process of production.

Over time, this led to the fact that all major high-speed interfaces and controllers "migrated" under the processor cover, and many motherboards of modern computers lost not only the southern, but sometimes the north bridge! Since all the peripheral controllers moved to the north bridge, the south just disappeared as unnecessary. Today you can still meet motherboards with the classic arrangement of the elements of the system logic (chipset), but this happens less and less.

So, let's continue! For cheaper motherboards, the situation is typical when manufacturers recruit all of its elements on the already shortened (from below or - on the side) plate of textolite. As a result, all the elements of the motherboard are located very close to each other and about some additional connectors or outputs have to be forgotten (here the main thing would fit everything!).

Remember: the aspect ratio of a good motherboard should be the same as in the photo (it should not be a small square or rectangular-elongated) and there must be a lot of space on it! Until now - this is my IMHO, despite the 2015 year :) Well-proven manufacturers of motherboards for desktop computers are companies: "Msi", "Asus" "Gigabyte" and "Intel".

For example, the company "Gigabyte" additionally "layers" several layers of copper between the layers of the printed circuit board. This proprietary technology even got its own name: "Ultra Durable" (photo at the beginning of the article). Copper acts as an additional radiator that removes heat from the hottest areas of the motherboard: the processor with its power circuits and chipset chipset.

Also, different boards manufacturers to add their products add to it all sorts of improvements: like a dual bios (in case of failure, do not use the programmer), a post-code sensor, power-on and reset buttons on the board itself, etc.

Here is one example of how to improve the quality of motherboards.

The bottom of the red is encircled by the POST code sensor, which we mentioned above. He can "tell" us about the problem in the work of the computer through digital combinations on the scoreboard. Their decoding, as a rule, is attached to the motherboard itself in the form of a small book.

But what other motherboards are there? The photo below is a form factor "micro ATX" with the "Atom 550" processor on passive cooling.

At the end of the article, I want to show you my workplace and how the next motherboard is tested on it:

Now I'm installing Windows. This type of connection allows to eliminate the cases of short circuit of the board on the computer case, and visual inspection and overall control over the process is much more convenient.

There are also server motherboards. What is the difference between server solutions and desktop (desktop) solutions? First of all, increased reliability! After all, servers have to work in 24/7 mode (as a supermarket) :) Servers are usually equipped with expensive register RAM with parity control (ECC), and they can support several physical processors. In the photo below, we see a board in which four physical CPUs can be installed.

This is already a product not related to the SOHO segment (Small Office / Home Office), but serious corporate solutions. Naturally, here, too, have their own Lov-End (cheap) and Hi-End (expensive) products, but that's another story. Also on servers, as a rule, hardware raids (RAID) controllers are created, made in the form of a separate printed circuit board, on the desktops such functionality can only be obtained by software.

Note: RAID (Redundant Array of Independent Disks is a redundant array of independent disks). The technology of reliable data storage based on the redundancy of stored information. Когда несколько жестких дисков объединяются в один виртуальный логический элемент для обеспечения надежности и повышения производительности.

Отдельно можно выделить геймерский сегмент материнских плат. Как правило, подобные решения стоят на порядок дороже и имеют кучу дополнительных опций: в виде продвинутых возможностей по разгону, расширенного управления питанием и охлаждением, различных датчиков индикации соcтояний, усиленной элементной базы и т.д. Одним из таких примеров являетcя изделие от фирмы Asus (Asus Maximus 7):

Геймерская материнская плата Геймерская материнская плата

Крутая «игрушка», правда? Напоследок, — мысль статьи, сформированная на основе личного опыта: хорошая (качественная) вещь не может стоить 30-50 долларов. Ну, вот не может и все тут! :)