MSI MS-6551 User Manual page 63

BIOS Setup
may just cause your overclocked processor to lock up.
CPU Host/3V66/PCI Clock
This item specifies the clock frequency of CPU host bus (FSB), Chipset,
AGP(3V66) and PCI bus and provides a method for end users to overclock
the processor accordingly. If the item shows Default, the clock frequency
will use the default value for both the CPU host bus and PCI bus.
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