Asus P8Z77-V LK Manual page 75

CPU PLL Voltage [Auto]
Allows you to set the CPU and PCH PLL voltage. The values range from 1.80V to 1.90V with
a 0.1V interval. Configuration options: [Auto] [+0.1V]
CPU Spread Spectrum [Auto]
[Auto] Automatic configuration.
[Disabled] Enhances the BCLK overclocking ability.
[Enabled] Sets to [Enabled] for EMI control.
ASUS P8Z77-V LK 3-13