Chapter 4 The Motherboard
You Will Learn… About the types of motherboards About components on the motherboard A basic procedure for building a computer How to install a motherboard How to troubleshoot a motherboard
Purpose of Motherboard Houses the CPU Allows all devices to communicate with the CPU and with each other
Types of Motherboards
ATX and AT Motherboards
Main Components on a Motherboard CPU and chip set System clock ROM BIOS CMOS configuration chip and its battery RAM RAM cache (optional) System bus with expansion slots Jumpers and DIP switches Ports that are directly on the board Power supply connections
Field Replaceable Units (FRUs) CPU ROM BIOS chip CMOS battery RAM RAM cache
An AT Motherboard
An ATX Motherboard
Components Determined by Motherboard Selection Types and speeds of CPU Chip set on the board (already installed) Memory cache and size Types/number of expansion slots: ISA, PCI, AGP Type of memory, including what kind and how much SRAM and DRAM (SIMMs, DIMMs, or RIMMs) Maximum amount of memory you can install; incremental amounts by which you can upgrade continued…
Components Determined by Motherboard Selection Type of case you can use ROM BIOS (already installed) Type of keyboard connector Presence/absence of proprietary video and/or proprietary local bus slots Presence/absence of IDE adapters and SCSI controller Presence/absence of COM ports, LPT ports, and mouse port
Approaches to Selecting a Motherboard 1. Provides most room for expansion 2. Suits needs of current configuration 3. Meets present needs with moderate room for expansion
When Selecting a Motherboard Designed so long expansion cards don’t get in the way of CPU or other devices? Support CPU you plan to use? What type of BIOS does it use? What bus speeds and type memory does it support; how much memory can it hold? Does it use many embedded devices? continued…
When Selecting a Motherboard Does it fit the case? Does it support your legacy cards? What is the warranty? Extensive user-friendly documentation? How much support does manufacturer supply?
Motherboard Manufacturers
The System Clock Keeps beat for motherboard activities Frequency measured in megahertz (MHz) Wait state Occurs when CPU must wait for another component
CPU and Chip Set IBM and IBM-compatible computers use a microprocessor chip made by Intel or AMD, and to a lesser degree by Cyrix
Attributes Used to Rate CPUs Speed (in gigahertz) Efficiency of programming code Number of transistors Number of registers Word size Data path Maximum number of memory addresses Amount of memory included Multiprocessing abilities Special functionality
The Pentium and Its Competitors Pentium processor A true multiprocessor (has two ALUs) 64-bit external path size and two 32-bit internal paths (one for each ALU)
CPU Terminology Bus speed Frequency/speed at which data moves on a bus Only the fastest bus connects directly to CPU Processor speed Speed at which CPU operates internally The multiplier System bus speed x multiplier = processor speed Memory cache Small amount of RAM that is fast and does not need refreshing Can hold data as long as power is available
Memory Cache on the CPU Internal cache, primary cache, or Level 1 cache Included on the CPU die External cache, secondary cache, or Level 2 cache Outside CPU microchip
Memory Cache on the CPU
The Pentium III
The Pentium 4
Advanced Pentium Competitors
The Cyrix III
The AMD Athlon
Intel Itanium: The Next-Generation Processor Intel’s first 64-bit processor for microcomputers Designed for high-end enterprise servers Uses a new instruction set called the EPIC (explicitly parallel instruction computing) architecture
Intel Itanium Processors
CPU Heat Sinks & Cooling Fans Heat sinks Used by older CPUs to pull heat away from the CPU Clip-on device that mounts on top of the CPU Cooling fans Keep temperatures below the Intel maximum limit of 185 degrees F/85 degrees C Exotic options: refrigeration, peltiers, water coolers
Heat Sinks and Cooling Fans
CPU Cooling Fan
CPU Package Types SECC (Single Edge Contact Cartridge) SECC2 (Single Edge Contact Cartridge, version 2) SEP (Single Edge Processor) PPGA (Plastic Pin Grid Array) PGA (Pin Grid Array) OOI/OLGA (Organic Land Grid Array) FC-PGA (Flip Chip Pin Grid Array) FC-PGA2 (Flip Chip Pin Grid Array 2) PAC (Pin Array Cartridge)
Plastic Pin Grid Array
CPU Slots and Sockets Physical connections used to connect CPU to motherboard Motherboard and processor must match Slots 1 and 2 are proprietary Intel slots Slot A and Socket A are proprietary AMD connectors
Sockets and Slots Used by CPUs continued…
Sockets and Slots Used by CPUs
CPU Slots and Sockets Earlier CPU sockets Pin grid array (PGA) sockets Staggered pin grid array (SPGA) Low insertion force (LIF) sockets Current CPU sockets Zero insertion force (ZIF) sockets; small lever on side of socket lifts CPU up and out of socket
CPU Slots and Sockets
CPU Voltage Regulator Controls the amount of voltage to the CPU Dual-voltage CPUs and single-voltage CPUs
The Chip Set Set of chips on system board that collectively controls memory cache, external buses, and some peripherals Intel dominates the market Most compatible with Pentium family of CPUs Investment in R&D has led to other developments (eg, PCI bus, universal serial bus, AGP, and Accelerated Hub Architecture)
Intel Chip Sets “E” chipset family Intel i800 Series Orion Natoma Triton III Triton II Triton I
Accelerated Hub Architecture
Chip Set Manufacturers
ROM BIOS One ROM chip on motherboard contains BIOS BIOS manages startup process (startup BIOS) and basic I/O functions (system BIOS) Most devices are not supported by system BIOS, but by device drivers Flash ROM (erasable programmable read-only memory or EEPROM) allows ROM BIOS to be upgraded without changing ROM chip
BIOS Manufacturers
Sample Web Site for Flash ROM BIOS Upgrades
Buses and Expansion Slots PCs have four or five buses, each with different speeds, access methods, and protocols Buses evolved around data path and speed So many buses because single speed is not practical Buses carry electrical power, control signals, memory addresses, and data On-board ports (eg, keyboard port and mouse port) Expansion slots can be located on motherboard; sometimes stacked vertically on a second board
Buses Listed by Throughput
Relationship of CPU Speed to Bus Speed Overall performance is better when multiplier is small Change speed of a computer by: Changing speed of system bus, or Changing multiplier that determines speed of CPU
How CPU and Bus Speeds Are Controlled
Hardware Configuration Tells CPU what hardware components are present and how they can interface with the CPU How much memory is available Which power management features are present Whether disk drives, hard drives, modems, serial ports are connected Provided on motherboard in three ways DIP switches Jumpers CMOS
Setup Data Stored by DIP Switches
Setup Data Stored by Jumpers
Setup Data on a CMOS Chip Also called real-time clock/nonvolatile RAM (RTC/NVRAM) chip Retains data even when computer is turned off Requires very little electricity to hold data Setup cannot be changed unintentionally, but disk drive must be working before you can change the setup
Changing CMOS Using Setup
Battery Power to CMOS Chip
Types of CMOS batteries 3.6V lithium battery with a four-pin connector; connects with a Velcro strip 4.5V alkaline battery with a four-pin connector; connects with a Velcro strip 3.6V barrel-style battery with a two-pin connector; soldered on 3V lithium coin-cell battery (most common)
Coin-Cell CMOS Battery
CMOS Setting startup passwords in CMOS Categories of CMOS settings Standard CMOS setup Advanced CMOS setup (aka BIOS Features setup) Advanced Chip Set Setup Power Menu (aka Power Management) IDE HDD Auto-detect Hardware Device Settings (on “jumperless” motherboards only)
Protecting Documentation and Configuration Settings Keep written record of CMOS settings, records of hardware and software installed, and network settings Keep well-labeled documentation in a safe place Saving and restoring CMOS settings using a third-party utility software
Building a Computer 1. Verify that you have all parts you plan to install 2. Prepare computer case 3. Install drives 4. Determine proper configuration settings for motherboard 5. Set jumpers or switches on motherboard 6. Install CPU and CPU cooler 7. Install RAM 8. Install motherboard and attach cabling continued…
Building a Computer 9. Install video card 10. Plug computer into power source; attach monitor and keyboard 11. Boot system and enter CMOS setup 12. Make sure settings are set to the default 13. If booting from a floppy disk, insert a bootable setup disk 14. Observe POST 15. Prepare hard drive for the OS continued…
Building a Computer 16. Reboot the system and run ScanDisk on drive C 17. Connect mouse 18. Install the OS from CD or floppy 19. Change boot order in CMOS 20. Check for conflicts with system resources 21. Install any other expansion cards, and/or drives 22. Verify that all is operating properly; make final OS and/or CMOS adjustments
Installing a Motherboard Prepare motherboard to go into the case Set jumpers Add CPU, fan, and heat sink Install motherboard in the case
Adding CPU, Fan, and Heat Sink
Installing the Motherboard in the Case 1.Install faceplate 2.Install standoffs 3.Place motherboard inside case and use screws to attach it to the case 4.Connect power cord from power supply to P1 power connection on motherboard 5.Connect wire leads from front panel of case to motherboard (reset switch, HDD LED, speaker, power LED, remote switch)
Installing the Faceplate
Standoffs and Screwholes
Wire Connectors
Completing the Installation Install drives and other components Turn on system and make sure everything is connected properly Set configuration data and create rescue desk of settings
Troubleshooting the Motherboard Look for clues from POST Reports errors as beep codes Cautiously substitute good hardware components for those you suspect are bad
Information about Beep Codes
Chapter Summary How the components of a computer work in harmony and with accuracy The motherboard Central site of computer logic circuitry Location of most important microchip in the computer, the CPU