Asus Crosshair IV Formula - Manual (Page 69)

4. Turbo Key II switch
This switch allows you to auto-tune your CPU to enhance the system
performance.
• If you clear the CMOS or load the BIOS setup defaults, the related
overclocking items in the BIOS menu follow the current setting of the Turbo
Key II switch.
• If you change the switch setting to Enable under the OS environment, the
Turbo Key II function will be activated after the next system bootup.
• You may use the TurboV Auto Tuning, overclock in the BIOS setup
program, and enable the Turbo Key II function at the same time. However,
the system will use the last setting you have made.
For ensuring the system performance, turn the switch setting to Enable when
the system is powered off.
ROG Crosshair IV Formula 2-43