MSI B550 GAMING PLUS Manuel D'utilisation page 41

EZ Debug LED
These LEDs indicate the debug status of the motherboard.
LED_SW1: EZ LED Control
This switch is used to switch on/ off all the LEDs of motherboard.
28
Overview of Components
CPU - indicates CPU is not detected or fail.
DRAM - indicates DRAM is not detected or fail.
VGA - indicates GPU/ PCIE/ M.2 device is not detected
or fail.
BOOT - indicates the booting device is not detected
or fail.
LED_OFF
LED_ON
(Default)