User guide

IMBA-9454G Motherboard
Page 140
BIOS SETUP UTILITY
Main Advanced PCIPnP Boot Security Chipset Exit
Southbridge Configuration

Spread Spectrum Mode [Disabled]
Audio Controller [AC’97 Audio]
Enable/Disable Spread
Spectrum modulation.
 Select Screen
  Select Item
+ - Change Option
F1 General Help
F10 Save and Exit
ESC Exit
v02.61 ©Copyright 1985-2006, American Megatrends, Inc.
BIOS Menu 23: Southbridge Chipset Configuration
 Spread Spectrum Mode [Disabled]
Use the Spread Spectrum option to reduce the EMI. Excess EMI is generated when the
system clock generator pulses have extreme values. Spreading the pulse spectrum
modulates changes in the extreme values from spikes to flat curves, thus reducing the
EMI. This benefit may in some cases be outweighed by problems with timing-critical
devices, such as a clock-sensitive SCSI device.


Disabled DEFAULT
EMI not reduced


Enabled
EMI reduced
 Audio Controller [AC’97 Audio]
Use the Audio Controller option to enable or disable the AC’97 CODEC.


AC’97 Audio DEFAULT
The onboard AC’97 is disabled


All Disabled
The onboard AC’97 automatically detected and
enabled