Specifications

AppendixEP-BXBS
A-11
Appendix D
CPU Clock Frequency selection in BIOS
There is a special function available in the BIOS to adjust the CPU bus frequency.
This allows the external clock to be modified depending upon what FSB has been
selected. For more information about selecting the FSB please see page 3-4. Once
you know what FSB is being used (66 or 100MHz) then it can be modified as
follows:
66MHz FSB options: 66.8 (default), 68.5, 75, and 83MHz.
100MHz FSB options: 100 (default), 103, 112, and 133MHz.
To modify the FSB follow the steps below:
1. Enter the BIOS CMOS utility by pressing the <Del> key during boot.
2. Choose “Chipset Features Setup.”
3. Select the option named “CPU Host Clock” and use the <Page Up> and <Page Down>
keys to select the desired frequency.
4. “Save and Exit setup” to complete the BIOS setting.
If the system can no longer boot after the above settings then you processor is not
supporting the modified frequencies. Use the following steps below to recover the
system:
1. Power the system off.
2. Press the <In> (insert) key while powering the system on. The system will now power
on using the default FSB.
3. Follow the steps above to modify the FSB and try again.
Warning: We do not guarantee CPUs will support modified fequencies. Frequency
use depends upon CPU design and the peripherals you are using; it’s vitally important
to use faster peripherals (faster SDRAM, I/O cards, etc) to support the higher
frequencies.