Motherboard

The motherboard, also known as the motherboard, motherboard, or main board ( motherboard or mainboard in English), is a printed circuit card to which the components that make up the computer are connected. In many Spanish-speaking places the English word is used with the feminine article.

It is a fundamental part to mount any desktop or laptop personal computer or some device. It has a series of integrated circuits installed, among which is the auxiliary integrated circuit (chipset), which serves as a connection center between the microprocessor (CPU), the memory Random Access Memory (RAM), expansion slots, and other devices.

It is installed inside a case or cabinet that is usually made of sheet metal and has a panel for connecting external devices and many internal connectors and sockets for installing internal components.

The motherboard also includes a firmware called BIOS, which allows it to perform basic functionalities, such as device testing, video and keyboard handling, device recognition, and operating system loading.

Motherboard Components

Diagram of a typical base plate.

A typical motherboard supports the following components:

• Power supply connectors.
• CPU (monoprocessor) or CPU sockets (multiprocessor).
• RAM Slots.
• Chipset.

Power connectors

ATX2-type power supply connectors for PC:
(1) mini molex for FDD.
(2) Universal Molex: for IDE devices, HDD and optical disk drive.
(3) for SATA devices.
(4) for 8 pin graphics cards, separable for 6 pins.
(5) for 6 pin graphics card.
(6) for 8 pin base plate.
(7) for CPU P4, combined for the connector of the base plate from 8 pins to 12V.
(8) 24 pin ATX2.

Through one or more of these power connectors, an electrical supply provides the motherboard with the different voltages and intensities necessary for its operation.

CPU ports

Base plate for personal desktop computer showing its typical components and interfaces. This model was manufactured by Foxconn in 2007 using the microATX layout, one of the most used for personal computers.

The CPU socket is a receptacle that encases the microprocessor and connects it to the rest of the components through the front-end bus of the motherboard.

If your motherboard has only one microprocessor socket, it is called a uniprocessor. On the other hand, if it has two or more sockets, it is called a multiprocessor card.

RAM Slots

Motherboards consist of slots (slots) of random access memory, their number is from 2 to 6 slots on a single common motherboard.

These memories of the appropriate type are inserted in them depending on the speed, capacity and manufacturer required according to the compatibility of each motherboard and CPU.

Chipset

The chipset is a series or set of electronic circuits that manage data transfers between the different components of the computer (processor, memory, graphics card, secondary storage unit, etc.).

The chipset, is generally divided into two sections:

1. North bridge (northbridge): manages the interconnection between the microprocessor, RAM and the graphic processing unit.
2. South bridge (southbridge): manages interconnection between peripherals and storage devices, such as hard drives or optical disk drives.

Newer lines of desktop processors tend to integrate the memory controller itself into the processor.

Other important components

• The watch: regulates the speed of execution of microprocessor and internal peripheral instructions.
• La CMOS: a small memory that preserves some important information (such as team configuration, date and time), while the equipment is not powered by electricity.
  • The stack of the CMOS: provides the electricity needed to operate the circuit constantly and the latter does not turn off by losing the series of saved configurations, such as date, time, start sequence...
• La BIOS: a program registered in a non-volatile memory (formerly in ROM memories, but long ago flash memories are used). This program is specific to the base plate and is responsible for the low-level interface between the microprocessor and some peripherals. Recovers, and then executes, the main boot log instructions (Master Boot Record, MBR), or registered on a hard drive or a solid state device, when you boot the operating system.
  • Currently, modern computers replace the MBR with the GUID partition table (GPT) and BIOS by Extensible Firmware Interface (EFI).
• The Front bus or front bus (front-side bus or FSB): also called “internal bus”, connects the microprocessor to chipset. He's falling into disuse in front of HyperTransport and Quickpath.
• The memory bus connects the chipset to temporary memory.
• The expansion bus (also called E/S bus): connects the microprocessor to input/output connectors and expansion slots.
• Input/output connectors that normally meet PC 99 standard; these connectors include:
  • The serial ports, to connect old devices.
  • The parallel ports, for the connection of old printers.
  • PS/2 ports to connect keyboard and mouse; these interfaces tend to be replaced by USB.
  • USB ports (in English) Universal Serial Bus), for example, to connect different peripherals, such as: mouse, keyboard, USB memory, smartphones, printers.
  • RJ-45 connectors, to connect to a computer network.
  • Connectors VGA, DVI, HDMI or DisplayPort for the connection of the computer monitor or video projector.
  • Connectors IDE or Serial ATA, to connect storage devices such as hard drives (HDD), solid state devices (SSD) and optical disk drives.
  • Connectors jacks audio, to connect audio devices, for example: speakers and headphones (color code: green), and microphones (color code: pink).
• The expansion slots: it is about receptacles (slots) that can host plates or expansion cards (these cards are used to add features or increase computer performance; for example, a graphic card can be added to improve 3D performance). These ports can be ports:
  • ISA (Industry Standard Architecture) ancient interface,
  • PCI (Peripheral Component Interconnect),
  • AGP (Accelerated Graphics PortAnd,
  • PCIe or PCI-ExpressThey're the most recent.

• With the evolution of computers, more and more features have been integrated into the base plate, such as electronic circuits for the management of video, sound or networks, thus avoiding the addition of expansion cards:
  • integrated graphical interface graphical processing unit (GPU, Graphics Processing Unitor IGP, Integrated Graphic Processor);
  • integrated audio or sound interface;
  • integrated Ethernet interface or integrated network ports ((10/100 Mbit/s)/(1 Gbit/s)).

• On the plate there are also different sets of pins, called jumpers or bridges, which serve to configure other devices:
  • JMDM1: Serve to connect a modem by which the system can be turned on when it receives a signal.
  • JIR2: This connector allows you to connect IrDA infrared modules, having to configure the BIOS.
  • JBAT1: It is used to delete all configurations that as a user we can modify and restore the configurations that come from factory.
  • JP20: Allows to connect audio to the front panel.
  • JFP1 & JFP2: It is used for connecting the front panel switches and LEDs.
  • JUSB1 and JUSB3: It is for connecting USB ports from the front panel.

Bus types

Dell T3600

Buses are physical spaces that allow the transport of information and energy between two points of the computer.

There are five general buses:

Data bus

The data buses are the communication lines through which the external and internal data of the microprocessor circulate.

Address Bus

The address bus is the communication line through which specific information travels about the location of the memory address of the data or device to which reference is made.

Control Bus

The control bus is the communication line through which the exchange of information with a module of the central unit and the peripherals is controlled.

Expansion bus

The expansion buses are the set of communication lines in charge of carrying the data bus, the address bus and the control bus to the interface card (input, output) that is added to the main board.

System bus

All components on the motherboard are linked via the system bus, using various types of data from the microprocessor and from main memory, which also involves the level 2 cache. system is determined by the bus frequency and width.

Motherboard formats

Motherboards need to have many dimensions compatible with the boxes that contain them, so that from the first personal computers mechanical characteristics, called form factor, have been established. They define the layout of various components and the physical dimensions, such as the length and width of the card, the position of the holes for the retaining screws, and the characteristics of the connectors.

Over the years, various standards were imposed.

XT

1983: XT (eXtended Technology) is the form factor of the IBM PC XT motherboard (model 5160), released in 1983. In this form factor, a size exactly equal to that of an A4 sheet and a single external connector for the keyboard were defined.

AT

1984: AT (Advanced Technology, «advanced technology») is one of the largest formats in the entire history of the PC (305×279–330 mm), defined a power connector formed by two parts. It was used extensively from 1985 to 1995.

• AT: 305×305 mm (IBM)
• Baby-AT: 216×330 mm

ATX

1995: ATX (Advanced Technology eXtended) Uses external connections in the form of an I/O panel and defined a 24-pin connector pins for power. It is currently used in the form of a few variants, including extra power connectors or reductions in size.

• ATX: 305×244 mm (Intel)
• microATX: 244×244 mm
• FlexATX: 229×191 mm
• MiniATX: 284×208 mm

ITX

2001: ITX (Information Technology eXtended), with cues from Intel's microATX and FlexATX specifications, the VIA design was It focuses on the integration of the largest possible number of components into the motherboard, in addition to the inclusion of the graphics hardware in the equipment's own chipset, making it unnecessary to install a graphics card in the AGP slot.

• ITX: 215×195 mm (VIA)
• Mini-ITX: 170×170 mm
• Nano-ITX: 120×120 mm
• Pico-ITX: 100×72 mm

BTX

2004: BTX (Balanced Technology eXtended, «extended balanced technology») was withdrawn in a very short time due to lack of acceptance, it was practically incompatible with ATX, except on the power supply. It was created to try to solve noise and cooling problems, as an evolution of the ATX.

• BTX: 325×267 mm (Intel)
• Micro BTX: 264×267 mm
• Pico BTX: 203×267 mm
• Regular BTX: 325×267 mm

DTX

2007: DTX were intended for small format PCs. They make use of a 24-pin power connector and an additional 2x2 connector.

• DTX: 248×203 mm (AMD)
• Mini DTX: 170×203 mm
• Full DTX: 243×203 mm

Proprietary formats

During the existence of the PC, many brands have tried to maintain a closed hardware scheme, called proprietary, manufacturing motherboards that are physically incompatible with form factors with dimensions, element distribution or connectors that are atypical. Among the most enduring brands is Dell, which rarely makes PCs designed with industry form factors.

Motherboard manufacturers

Several manufacturers share the motherboard market, such as: Advantech, Albatron, Aopen, ASUS, AsRock, Biostar, Chaintech, Dell, DFI, ECS EliteGroup, FIC, Foxconn, Gigabyte Technology, iBase, iEi, Intel, Lenovo, MSI, PC Chips, Sapphire Technology, Super Micro, Tyan, VIA, XFX, Zotac.

Some design and manufacture one or more motherboard components, while others assemble components that others have designed and manufactured.

Types of main boards

Most PC boards manufactured after 2001 can be classified into two groups:

• AMD microprocessor base plates:
  • Slot A: Duron, Athlon
  • Socket A: Duron, Athlon, Athlon XP, Sempron
  • Socket 754: Athlon 64, Mobile Athlon 64, Sempron, Turion
  • Socket 939: Athlon 64, Athlon FX Athlon X2, Sempron, Opteron
  • Socket 940: Opteron and Athlon 64 FX
  • Socket AM2: Athlon 64, Athlon FX, Athlon X2, Sempron, Phenom
  • Socket F: Opteron
  • Socket AM2 +: Athlon 64, Athlon FX, Athlon X2, Sempron, Phenom
  • Socket AM3: Phenom II X2/X3/X4/x6, Athlon II X2/X3/X4, Sempron 100 Series
  • Socket AM3+: Sempron, Athlon II X2/X3/X4, Phenom II X2/X3/X4/X6, FX X4/X6/X8
  • Socket FM1: A4X2, A6X3/X4, A8X4, Athlon II
  • Socket FM2: APU A4, APU A6, APU A8, APU A10, Athlon II X2/X4
  • Socket AM4: Zen architecture processors

• The base plates for Intel microprocessors:
  • Socket 7: Pentium I, Pentium MMX
  • Slot 1: Pentium II, Pentium III, Celeron
  • Socket 370: Pentium III, Celeron
  • Socket 423: Pentium 4
  • Socket 478: Pentium 4, Celeron
  • LGA 775: Pentium 4, Celeron, Pentium D (double core), Core 2 Duo, Core 2 Quad, Core 2 Extreme, Xeon
  • Socket 603: Xeon
  • Socket 604: Xeon
  • Socket 771: Xeon
  • LGA 1366: Intel Core i7 (Nehalem), Xeon (Nehalem)
  • LGA 1156: Intel Core i3, Intel Core i5, Intel Core i7 (Nehalem)
  • LGA 2011: Intel Core i7, Xeon (Sandy Bridge)
  • LGA 1155: Intel Core i5 and Intel Core i3 (Sandy Bridge), Intel Core i7, Intel Core i5 and Intel Core i3 (Ivy Bridge)
  • LGA 1150: Intel Core i7, Intel Core i5 and Intel Core i3 (Haswell and Broadwell)
  • LGA 1151: Intel Core i7, Intel Core i5, Intel Core i3, Intel Pentium G4000/G5000 series and Intel Celeron G3900 series (Skylake) and (Kaby Lake)
  • LGA 1200: Core i9, Core i7, Core i5, Core i3, Pentium Gold, Celeron.

Multiprocessor board

A plate with two processors.

This type of motherboard includes sockets for installing multiple processors (usually 2, 4, 8, or more). We are not referring to installing a processor with several cores, but to the fact that we can install several physical processors. Some manufacturers provide motherboards that can host up to 8 processors (in the case of socket 939 for AMD Opteron processors and on socket 604 for Intel Xeon processors).