Asus M4A89GTD PRO/USB3 - Manual (Page 58)

2-40 Chapter 2: Hardware information
Chapter 2
3. Turbo Key II LED
The Turbo Key II LED lights when the Turbo Key II switch is turned to
Enable.
4. Core Unlocker LED
The Core Unlocker LED lights when the Core Unclocker switch is turned to
Enable.
The Core Unlocker LED keeps on lighting even though the ASUS Core Unlocker item in
the BIOS menu is set to [Disabled].