Power1, Reset1: Power Button, Reset Button; Plus, Minus Buttons: Bclk-Ratio Buttons - MSI X299 XPOWER GAMING AC Quick Start Manual

POWER1, RESET1: Power Button, Reset Button

The Power / Reset button allows you to power on / reset the computer.

Plus, Minus buttons: BCLK-Ratio buttons

You can use these buttons to increase or decrease the CPU BCLK/ Ratio.
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Overview of Components
Power button
BCLK+
/ Ratio+
Reset button
BCLK-
/ Ratio-