VIA Technologies KM400, User Manual

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Introduction
Page 1-4
Mainboard Form-Factor
This board is designed with M-ATX form factor - the latest industry standard for
chassis design. The M-ATX form factor is essentially a Baby-AT baseboard
rotated 90 degrees within the chassis enclosure and a new mounting configura-
tion 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. M-
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
ATX
Power
Supply
ATX power connector
IDE connectors
AGP slot
3 1/2-inch
Bay
5 1/4-inch
Bay
Floppy
connector