MSI Z87 XPOWER - Manual (Page 54)

Chapter 1
1-40 Getting Started
LED Status Indicators
BIOS LEDs
These LEDs are used to distinguish BIOS A or B is in operation.
When the left LED lights blue, the BIOS A is in operation.
When the right LED lights green, the BIOS B is in operation.
HDD LED
This LED will flash whenever there's a disk activity.
OC Switch Mode LEDs
These LEDs are used to indicate OC Genie operation mode.
When the bottom LED lights blue, the OC Genie operation mode is Gear 1.
When the top LED lights red, the OC Genie operation mode is Gear 2.
BIOS LEDs
HDD LED
2-Digit Debug Code LED
OC Switch Mode LEDs