1. Motherboards
Chapter 7

2. How Motherboards Work
The motherboard determines the function, expansion, and stability of the PC
Form Factors
Industry-standardized shapes and layouts
Plays a big part in air flow. Must match the case and power supply.
AT Form Factor
Came out in the IBM PC/AT
LPX – low profile extended
NLX
Riser slot for daughterboard
ATX Form Factor
Figure 7-7
No AT keyboard port
microATX
FlexATX
ITX
Mini-ITX, Nano-ITX, Pico-ITX
Proprietary Form Factors

3. How Motherboards Work Chipset Northbridge Southbridge Super I/O chip
Dealt with CPU, RAM, and video card
Fast, frontside bus
Southbridge
Handles expansion bus and mass storage devices
Super I/O chip
Figure 7-13
ROM
Hold BIOS
Newer Terminology
Memory Controller Hub (MCH)
I/O Controller Hub (ICH)

4. How Motherboards Work Motherboard Components USB/FireWire Sound RAID
Redundant array of independent disks
Mirror or striping
AMR/CNR
Audio modem riser
Communications and network riser
Case Fan Support

5. Expansion Bus Structure and Function of the Expansion Bus PCI AGP
Figures 7-20, 7-21, 7-22
Expansion bus crystal
PCI
Peripheral Component Interconnect
32 bits wide at 33 MHz
PnP devices
Burst mode
AGP
Accelerated Graphics Port
Direct connection to Northbridge
PCI-X
PCI eXtended
64 bits wide at 66, 133, 266, and 533 MHz
Mini-PCI
Figure 7-29
PCI Express
Point-to-point serial communications
No bus sharing
2.5 Gbps or 5.0 Gbps per lane