Asus Z87-K - Manual (Page 63)

2-36 Chapter 2: Getting started
Chassis1/2 Fan Min. Duty Cycle(%) [60]
Use the <+> and <-> keys to adjust the minimum chassis fan duty cycle. The values
range from 60% to 100%. When the chassis temperature is under 40ºC, the chassis
fan will operate at the minimum duty cycle.
2.7.6 Anti Surge Support [Enabled]
This item allows you to enable or disable the Anti Surge function.
Configuration options: [Disabled] [Enabled]
2.8 Boot menu
The Boot menu items allow you to change the system boot options.
Scroll down to display the following items: