the motherboard. objectives after completing this section you will: understand the major components...

The Motherboard

Objectives

After completing this section you will:

• Understand the major components on a motherboard including the

microprocessor, chipset, math coprocessor, and expansion slots.

• Understand the basic operation of a microprocessor and what issues

must be considered when upgrading it.

• Recognize and identify the microprocessor.

• Understand the differences among the various architectures and buses.

• Recognize different expansion slots.

• Recognize an adapter’s architecture or bus.

Microprocessor Overview

• Microprocessor (or processor)

• CPU (Central Processing Unit)

• Clones – IBM compatibles

• PC – Stands for Personal Computer, another name for the

microcomputer.

We will focus on compatibles (or non-Apple computers) because they

make up the majority of computers in use today.

Because Intel and AMD are the microprocessors primarily used in

today’s computer industry, they are the examples covered extensively in

this material.

Microprocessor Basics

• Bit – Either a 1 or 0. All microprocessors use 1s and 0s to calculate or

interpret information.

• Byte – Eight bits grouped together, the letter A looks like 01000001 to

the processor. Each character on the keyboard appears as one byte (or

eight bits) to the CPU. Denoted by the letter B, thirty-two bytes is 32B.

• Kilobyte – Approximately 1,000 bytes (1,024 exactly, but rounded off by

the industry to the nearest thousand for ease of calculation). Shown as K

or KB, ten kilobytes is shown as 10K or 10KB.

• Megabyte – Approximately one million bytes and referenced by M or

MB. 540 megabytes is shown as 540M or 540MB.

• Gigabyte – Approximately 1 billion bytes (1,073,741,824) and written as

1G or 1 GB.


Motherboard – Table #1


• Gigahertz (GHz) Hertz is a measurement of cycles per second (or

frequency). One hertz equals one cycle per second. One megahertz

(1MHz) is equal to one million cycles per second, one gigahertz (1GHz)

is one billion cycles per second. For comparison, the 8088

microprocessor ran at 4.77 MHz, today’s CPUs run at over 2 GHz!

• Register size – The number of bits processed at one time by the

processor. Counted in multiples of 8 bits, such as 8-, 16-, and 32-bit

register size. Sometimes referred to as word size by the computer

industry. Intel’s 8086 processor’s word size was 16 bits or 2 bytes. Most

microprocessors today have 64-bit or 128-bit register sizes.

• Bus – Electronic lines to move the 1s and 0s inside the computer.


• Internal data bus – Moves the 1s and 0s inside the microprocessor. In

the 8086, there are 16 separate electronic lines, each carrying one 1 or

one 0. The word size and internal data bus were the same size, 16-bit.

• External data bus – Used to connect the microprocessor to adapters,

storage devices, and peripherals. Also called the external data path,

these lines connect to ports and expansion slots. The Intel 8088 had an

8-bit external data bus. Today’s CPUs have 64-bit external data paths.

• Today’s microprocessors have 64-bit or 128-bit internal data bus lines

and external data paths.


Motherboard – Figure #1

Internal and External Data Buses



Intel Microprocessors


• Pipelines – Separate (multiple) internal buses that operate

simultaneously. This allows tasks and instructions to be broken down into

smaller and more numerous parts, which permits the CPU to act on them

more quickly and efficiently, improving computer performance.

• SEC (Single Edge Contact) cartridge – Used with an Intel Slot 1

connector on Intel’s Pentium II microprocessor to reach speeds of

300MHz.

• SEPP (Single Edge Processor Package) cartridge – Similar to the

Pentium II SEC and used with the Intel Celeron processor.


Intel Microprocessors




Intel CPU Sockets and Slots

AMD Processors

• AMD (Advanced Micro Devices, Inc.) – Produces a microprocessor

similar to the Intel processors.

• Super 7 Socket – Redesigned Socket 7 that allows for higher bus

speeds (66 to 95 or 100MHz). Super 7 motherboards allow higher CPU

speeds, support for AGP and Ultra DMA hard drives, and have advanced

power management features.

• Socket A – 462-pin PGA socket for the AMD Athlon and Duron CPUs.

• Slot A – Used by early AMD Athlon processors similar to Intel Pentium

III, but they are not interchangeable.

AMD Processors

AMD’s Socket A


AMD Processors

AMD Athlon


AMD Processors


AMD CPU Sockets and Slots

MMX, SSE, and 3DNOW!

• MMX – A microprocessor technology from Intel that adds 57 instructions

to an Intel processor to help with multimedia and communications

software.

• SSE (Streaming SIMD Extensions) – Intel’s processor technology that

speeds up 3-D applications by allowing instructions to be used by

multiple data items. There are 50 instructions allowing floating-point

calculations to occur simultaneously.

• 3DNOW! – 21 instructions and support for SIMD added to an AMD

processor for 3-D applications.

Processor Speeds and Cooling

Microprocessors and math coprocessors come in many speeds and this

is measured in gigahertz (GHz). Hertz is a measurement of cycles per

second (or frequency). One hertz equals one cycle per second. One

megahertz (1MHz) is equal to one million cycles per second, one

gigahertz (1GHz) is one billion cycles per second.

The faster the microprocessor runs, the hotter it gets. Many processors

now have heat sinks (metal bars protruding from the CPU to form a basic

radiator) or small fans for cooling. In many cases, today’s processors

have both. Some systems even have multiple fans to prevent damage to

the processor and internal components due to the amount of heat being

generated.

• Liquid cooling system – liquid is circulated through the system,

including through a heat sink that is mounted on the CPU. It allows

higher clock speeds and is quieter than a fan.


Microprocessor Speeds



Microprocessor Fan and Heat Sink



• Other things to know when determining processor speeds:

– Jumper – Small metal connector with a plastic cover used to connect

two metal pins together. Configuring the jumpers on a motherboard

will change the settings on that board.

– Multiplier – A number that is multiplied by the bus speed to

determine the CPU speed.

• Example: 60MHz bus speed x 1.5(multiplier) = 90MHz CPU


CPU with Heat Sink and Fan



JP1 Jumper Block with Pins 1 and 2 Jumpered Together


Cache Memory

• Cache memory – A fast type of memory designed to increase the speed

of microprocessor operations.

• L1 (Level one) cache – Cache memory that is located inside the

microprocessor.

• Write-through cache – The microprocessor writes 1s and 0s into the

cache memory at the same time as regular memory.

• Write-back cache – The 1s and 0s are written to regular memory when

the microprocessor is not busy. It is more efficient than write-through

cache.

• L2 cache – Cache memory that is on the motherboard for Pentium and

lower processors. Starting with the Pentium Pro processor, the L2

cache is inside the processor packaging and known as on-die cache.

Cache Memory

• L3 cache – L1 and L2 cache are included with the processor packaging.

• COAST (Cache On A STick) – Cache chips on the motherboard that

resemble a small SIMM.

• DIB (Dual Independent Bus) – Two buses used for the processor to

communicate with motherboard components.

• FSB (front side bus) – connects a CPU to the motherboard

components.

• Back side bus – connects the CPU to the L2 cache.

Cache Memory

Front Side Bus


Microprocessor Study Guides

Intel Microprocessor Study Table


Microprocessor Study Guides

AMD Processors


Microprocessor Upgrade Overview

Always refer to the motherboard’s documentation when upgrading the

processor. It allows you to choose the proper processor and prevent

damage to the processor and motherboard.

• VRM (Voltage Regulator Module) – Provides the appropriate voltage

for microprocessors. It is usually found on Socket 7 or Socket 8 for

Pentiums.

Installing and Overclocking Microprocessors

• Always refer to the motherboard manuals for the installation steps to

upgrade or install the processor. Your book contains general instructions

for upgrading and installing the microprocessor beginning on page 2-25.

• Overclocking – Changing the front-side bus speed or the multiplier to

boost the CPU speed or system speed. This can cause damage to the

CPU, motherboard, or other components.

Installing and Overclocking Microprocessors


Computer Case Auxiliary Fans

Dual Processors

• Adding another (or dual) processor can greatly enhance computer

performance. Most home and business users do not require an additional

processor, however most servers do.

• Follow all manufacturers documentation on selecting an additional

processor, installing it, and configuring the motherboard with dual

processors.

• Its important to add RAM if possible when adding a second processor.

Put in as much RAM as the customer can afford to improve performance.

A general rule of thumb is to double the RAM when adding a second

processor.

Motherboard Troubleshooting

Motherboard and power problems are probably the most difficult things to

troubleshoot. A good general list of motherboard troubleshooting tips can

be found on page 2-29 in your book.

Expansion Slots

• Expansion slots allow adapters to be installed into the motherboard to

add capabilities to the PC.

• Technicians must be able to identify expansion slots and distinguish

between the adapters that use them.

• The technician must be able to install the proper adapter in the correct

expansion slot and configure both correctly.

ISA (Industry Standard Architecture)

• ISA (Industry Standard Architecture) – The oldest expansion slot that

is configured in 8-Bit and 16-Bit slots.

– Also referred to as the AT bus.

– Operates at 8MHz, although some manufacturers reliably achieve a

throughput of 10 MHz.


EISA (Extended Industry Standard Architecture)

• EISA (Enhanced Industry Standard Architecture) – 32-bit expansion

slot that is the same length as an ISA slot and twice as deep.

– A non-proprietary architecture developed by a group of nine vendors

in response to IBM’s proprietary MicroChannel Architecture.

– A 32-bit, 10MHz standard that also allows ISA adapters to operate in

the expansion slots.

– This standard was never as successful as the designers hoped.

PCI (Peripheral Component Interconnect)

• PCI (Peripheral Component Interconnect) – The most popular

expansion slot that is configured in both 32-bit, 33MHz and 64-bit, at

33MHz and 66MHz.

• A new standard is the PCI-X which can operate at 66MHz, 133MHz,

266MHz, and 533MHz. PCI-X 1066MHz is being developed.

• PCI adapters are configured with software and the standard supports

bus-mastering, which allows an adapter to take over the external bus

from the CPU and execute operations with another bus-mastering

adapter without going through the processor.


PCI-X Block Diagram



3.3 Volt and 5 Volt PCI Expansion Slots


Mini PCI

• Mini PCI – 32-bit, 33MHz standard was developed to allow PCI

upgrades and interface cards to be added to laptops, docking stations,

and printers. Mini-PCI cards have 3 form factors; Type I, Type II, and

Type III.


Mini PCI Adapter

Installed in Laptop

AGP (Accelerated Graphics Port)

• AGP (Accelerated Graphics Port) – 32-bit bus interface for graphics

adapters developed from the PCI bus.

– It speeds up 3-D graphics, 3-D acceleration, and full-motion playback.

– Allows the video adapter to directly access RAM on the motherboard

when needed.

– The video subsystem is isolated from the rest of the computer.

– In order to implement AGP, the motherboard must have an AGP

expansion slot, the chipset must support AGP, and an operating

system that supports AGP must be installed.

– Some motherboards will allow changing the amount of memory AGP

can use. The amount normally used is 64MB, configured through

BIOS settings, and referred to as the AGP Aperture.


AGP Versions



AGP Expansion Slot


More Motherboard Connectors

• AMR (Audio/Modem Riser) – Connector on the motherboard for

combination audio and modem adapters without taking up a PCI slot.

• CNR (Communications Network Riser) – Intel’s design that allows the

integration of network, audio, and modem functions. It shares a PCI slot

and is located beside or between other motherboard expansion slots.

• ACR (Advanced Communication Riser) – Technology that supports

audio, modem, networking, and DSL modems. It was developed by a

group of companies including AMD, VIA Technologies, Motorola, and

3Com.

Future Buses

• HyperTransport – AMD’s futuristic I/O architecture in which a serial-link

design allows devices to communicate in a daisy chain fashion.

• InfiniBand – A futuristic I/O architecture wherein point-to-point device

connections are made through a switching fabric.

• HCA (Host Channel Adapter) – Connects memory to a switch fabric

and is used in the InfiniBand bus architecture.

• TCA (Target Channel Adapter) – An adapter that connects end devices

to the switch fabric and is used in the InfiniBand architecture.

• RapidIO – A futuristic I/O architecture that supports interconnections for

chip-to-chip, board-to-board, and device-to-device.

Proprietary Expansion Slots

Some older computers have an expansion slot built into the motherboard

that are neither ISA nor PCI. These are proprietary expansion slots that

only fit proprietary adapter cards. These are only available from the

expansion slot manufacturer (if still supported) and usually expensive.

USB (Universal Serial Bus)

• USB (Universal Serial Bus) – Allows connection of up to 127 external

devices without degradation of speed. Can be used by many types of

devices as long as the operating system supports USB.

– Original USB includes two speeds:

• 1.5Mbps for keyboards and mice.

• 12Mbps for modems, CD/DVD drives, printers, scanners,

monitors, and digital cameras.

– USB version 2.0 supports speeds up to 480Mbps for

videoconferencing cameras, higher resolution printers and scanners.

It is backward compatible for USB 1.1 devices.

– USB has two types of USB ports and connectors – Type A and Type

B.

USB (Universal Serial Bus)

USB Type A and Type B Connectors


IEEE 1394 (FireWire or I.Link)

• IEEE 1394 – known as FireWire and supports up to 63 devices. It is able

to support digital audio and video devices.

– Supports plug and play like USB and the devices are hot swappable.

– The IEEE 1394 bus is actually a peer-to peer standard meaning a

computer is not needed to use it, such as connecting a digital camera

directly to a hard drive to transfer picture files.

– Designed to support high-speed audio and video devices with greater

throughput for applications such as video conferencing.

– All versions of IEEE 1394 support speeds of 100, 200, 400, 800 or

1200 Mbps and a maximum distance of 236 feet or 328 feet for

IEEE1394b.

IEEE 1394 (FireWire or I.Link)

• IEEE 1394 – known as FireWire and supports up to 63 devices. It is able

to support digital audio and video devices.


PC Card

• PC Card – Previously known as PCMCIA (Personal Computer Memory

Card International Association). It is used for modems, hard drives,

network adapters, etc. in laptop computers.

• CardBus – Allows 32-bit transfers at speeds up to 33MHz.

• SmartMedia – Holds pictures and audio files and is used with digital

cameras, PDAs, etc.

• ZV port (Zoomed Video Port) – Allows direct data transfer from a PC

Card to a video controller. Data transfers over the ZV bus instead of the

system bus.

• CardBay – Allows laptop computers to be compatible with the USB and

IEEE 1394 serial interfaces.

PC Card

PC Card


PC Card

PC Cards


PC Card

Expansion Slot or Port Overview


Chipsets

• Chipset – The principle chips on the motherboard that work in

conjunction with the microprocessor and allow features on a computer.

• For example, they control:

– Maximum amount of motherboard memory

– The type of RAM chips

– The motherboard’s capacity for multiple processors

– Support for the latest version of PCI

Types of Motherboards

• Form Factors – The different sizes of motherboards.

• The most common motherboards are:

– AT: named after IBM’s original AT computer motherboard.

– Baby AT: smaller size of the AT.

– ATX: similar to baby AT, but rotated 90 degrees.

– NLX: designed around Pentium II and higher, allows more expansion.

– MicroATX: max size is 9.6 inches by 9.6 inches, fits ATX case.

– FlexATX: 9 inches by 7.5 inches and backward compatible with ATX and

MicroATX.

– ITX: 8.5 inches by 7.5 inches and made for a smaller power supply.

– WTX: for large workstations and servers.

Types of Motherboards

NLX Motherboard


Upgrading and Replacing Motherboards

• There are several issues to be taken into account when upgrading a

motherboard:

– Memory

– Adapter types

– Type of case

– Microprocessor

– Chipsets

– Hard drive

– Power supply

– Future upgrade-ability

– There is a basic guide on page 2-51

the motherboard. objectives after completing this section you will: understand the major components...

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