MSI MS-6398 Technical Manual page 61

Chapter 3
CPU Host/3V66/PCI Clock
This setting controls the clock frequency of the CPU host bus (FSB)/3V66/PCI
bus on the motherboard.
CPU Vcore Adjust
This setting allows you to adjust the CPU core voltage from 1.475V to 1.6V.
Please note that it may be dangerous to adjust the Vcore over 10%.
Note: Changing CPU Vcore could result in unstable system;
therefore, it is not recommended to change the default setting for
long-term purpose.
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