Asus RS926-E7/RS8 - Manual (Page 72)

4-18 Chapter 4: Motherboard information
4.4 Internal LEDs
1. Standby Power LED (SB_PWR1)
The motherboard comes with a standby power LED. The green LED lights up
to indicate the system AC power cable plug or not. This is a reminder that you
should shut down the system and unplug the power cable before removing
or plugging in any motherboard component. The illustration below shows the
location of the onboard LED.
2. DIMM warning LED (ERR_DIMM)
The DIMM warning LEDs light up to indicate an impending failure of the
corresponding DIMMs.
The warning LEDs function only when you install the ASUS ASMB6.