MSI ATX BX13 User Manual page 23

2.1-3 CPU Bus Frequency Selector: SW2
The SW2 is used to set the CPU Bus Frequencies from 66MHz to 100MHz.
When SW2 is shorted, this will automatically detect the CPU Bus Frequency.
When SW2 is open, if you used 66MHz CPU Bus Frequency, this will set it
virtually into 100MHz.
SW2
NOTE: 1. This feature works with 66MHz FSB only.
2. If your CPU FSB supports 66MHz and you want to run it
on 100MHz FSB, the SW2 should be open. The AGP Bus will
be set to run at 100MHz x 2/3=66MHz to make it stable.
Feature
Automatically detect 66MHz and
100MHz CPU Bus Frequency
Virtually set 66MHz CPU Bus
Frequency into 100MHz
2-18
SW2