4.2 What is on the Motherboard

The motherboard contains many different integrated circuits that help get its job done. This section discusses the most common elements found on motherboards.

The Chipset - What does it do?

The chipset is responsible for handling communications between the CPU, the computer’s RAM, and the various expansion slots and devices. If the motherboard is the “nervous system” of the PC, the chipset is the spinal cord.

Why is it important?

The chipset determines the most important capabilities of the computer:

  • The CPU that can be used
  • The type and amount of RAM that can be installed into the system
  • Which type of components can be added
  • Overall efficiency

An inefficient chipset will slow down a computer with the best components. Poorly designed chipsets can cause the computer to have intermittent problems that even the best technician may have trouble diagnosing.

Main Power Connector

The motherboard has a main connector for electricity from the power supply.

Power is distributed from this connection to the various circuits on the motherboard.

The motherboard even provides power to the cards plugged into its expansions slots.

Fan Power Points

Many motherboards have connectors that allow cooling fans to be connected to the motherboard.

The motherboard supplies electricity to the fans and can monitor the fans to make sure they are functioning.

Some motherboards can even slow down and speed up the fans, depending on the amount of cooling needed.

 

CPU Interface

The CPU (Central Processing Unit) interface provides a connection point for the CPU to the motherboard.

There are many different interfaces to support the many different CPUs available.

The motherboard’s documentation will indicate the type of CPUs that can be supported.


RAM Sockets

The RAM (Random Access Memory) socket provides a connection point to add RAM to the motherboard.

There are a few different types of RAM.
The appropriate RAM must be installed onto the motherboard. Refer to the motherboard’s documentation to find out which types of RAM are supported.

Other Motherboard Components

I/O Ports

Older AT style motherboards will have a 5-pin DIN port. Parallel ports and serial port(s) may be integrated into the motherboard or attached indirectly with cables to the motherboard.

Current I/O Ports include:

  • PS/2 6 pin circular interface is used by keyboards; it is becoming less popular with the advent of USB keyboards.

  • USB (Universal Serial Bus) ports permit connections to the motherboard for up to 127 devices. Multiple devices are connected by plugging a hub into the USB port and attaching the devices to the hub. Because they accept so many devices and support both data-dense devices like scanners and data-light devices like mice, USB ports are standard on all motherboards.

  • FireWire: Connection used for enhanced audio/video transfer, especially useful with digital video cameras

  • eSATA Like USB and FireWire ports, this port allows user to plug in eSATA external connector for compatible devices

  • S/PDIF (Sony/Philips Digital Interconnect Format) allows users to connect audio from a DVD player to a receiver

  • Ethernet Port: Allows user to connect directly to a LAN, DSL modem, or cable modem

  • Audio Connectors: Allows user to plug in audio devices for speakers or headphones for private listening

Expansion Slots

Other expansion slots may be included with the motherboard. Some are less common, like CNR and AMR, or may soon be obsolete as the EISA. Some are newer like the AGP Pro.

ISA was one of the first expansion slots. The fastest ISA bus transferred data at 8 MHz with a 16-bit bus width. ISA is obsolete due to slow speeds and the creation of the PCI expansion slot.

PCI may be used for low end audio, graphic, and other various expansion cards. The PCI bus transfers data at 33 MHz and has either a 32-bit or 64-bit bus width. The PCI bus has a data transfer rate of 266 MB per second up to 1014 MB per second.

PCI Express(PCIe) is the most current expansion slot. PCIe uses an extremely fast 1 bit lane instead of the large but slow 16, 32, or 64 bit bus used by previous expansion slots. PCIe can have multiple lanes. Each lane has a bandwidth of about 500 MB per second making it much faster than PCI. The fastest version of PCIe beats the fastest version of AGP, making it the most promising expansion slot on the market.

AGP is used for high end graphic cards. It uses a 32-bit bus and transfers data at 66 MHz. The AGP bus has a data transfer rate of 133 MB per second up to 2133 MB per second.

AGP Pro is used for high end professional graphic cards. AGP Pro is used to speed up the processing of computer-aided design in the fields of engineering, architecture, and other 3D softwares.