Mach P4MST-890 Setup Manual page 26

Motherboard Manual
3. Voltage Panel
Click the Voltage button in Main Panel, the button will be highlighted
and the Voltage Panel will slide out to up as the following figure.
In this panel, you can decide to increase CPU core voltage and
Memory voltage or not. The default setting is "No". If you want to get
the best performance of overclocking, we recommend you click the
option "Yes".
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