MSI Z87 MPOWER - Manual (Page 53)

Chapter 1
1-39 Getting Started
LED Status Indicators
BIOS LEDs
These LEDs are used to distinguish BIOS A or B is in operation.
When the bottom LED lights blue, the BIOS A is in operation.
When the top LED lights green, the BIOS B is in operation.
HDD_LED
This LED will flash whenever there's a disk activity.
OC Switch LEDs
These LEDs are used to indicate OC Genie operation mode.
When the left LED lights blue, the OC Genie operation mode is Gear1.
When the right LED lights red, the OC Genie operation mode is Gear2.
BIOS LEDs
HDD LED
2-Digit Debug Code LED
OC Switch LEDs