MSI Z97 XPOWER AC Manual page 42

BCLK+, BCLK-: Base Clock Control Buttons
These buttons are used to increase or decrease the base clock frequency. Pressing
the Plus/ Minus button once will increase/ decrease the base clock frequency 1 MHz
when the system is in regular operation state.
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RATIO+, RATIO-: CPU Ratio Control Buttons
These buttons are used to increase or decrease the CPU ratio. Pressing the Plus/
Minus button once will increase/ decrease the CPU ratio when the system is in
regular operation state.
1 2 3 4
Plus button:
Base clock + 1 MHz
Plus button:
CPU RATIO + 1
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Minus button:
Base clock - 1 MHz
Minus button:
CPU RATIO - 1