VIA Technologies KT400A, User Manual

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Introduction
Page 1-4
Mainboard Form-Factor
This board is designed with ATX form factor - the latest industry standard for
chassis design. The ATX form factor is essentially a Baby-AT baseboard rotated
90 degrees within the chassis enclosure and a new mounting configuration for
the power supply. With these changes the processor is relocated away from the
expansion slots, allowing them all to hold full length add-in cards. ATX defines a
double height aperture to the rear of the chassis which can be used to host a
wide range of onboard I/O. Only the size and position of this aperture is defined,
allowing PC manufacturers to add new I/O features (e.g.; TV input, TV output,
joystick, modem, LAN, audio, etc.) to systems. This will help systems integrators
differentiate their products in the marketplace, and better meet your needs.
• By integrating more I/O down onto the board and better positioning the hard
drive and floppy connectors, material cost of cables and add-in cards are
reduced.
• By reducing the number of cables and components in the system, manufac-
turing time and inventory holding costs are reduced and reliability will
increase.
• By using an optimized power supply, it's possible to reduce cooling costs
and lower acoustical noise. An ATX power supply, which has a side-
mounted fan, allows direct cooling of the processor and add-in cards making
a secondary fan or active heatsink unnecessary in most system applications.
PCI slots
Expandable I/O
Figure 2: Summary of ATX chassis features
CPU socket
Single chassis
fan for system
AT X
Power
Supply
ATX power connector
IDE connectors
AGP slot
3 1/2-inch
Bay
5 1/4-inch
Bay
Floppy
connector