Asus KGPE-D16 - Manual (Page 24)

2-4 Chapter 2: Hardware information
2. CPU warning LED (ERR_CPU1, ERR_CPU2)
The CPU warning LEDs light up to indicate that an impending failure of the
corresponding CPU.
3. DIMM warning LED (ERR_DIMMA1/2; ERR_DIMMB1/2; ERR_DIMMC1/2;
ERR_DIMMD1/2; ERR_DIMME1/2; ERR_DIMMF1/2; ERR_DIMMG1/2;
ERR_DIMMH1/2)
The DIMM warning LEDs light up to indicate that an impending failure of the
corresponding DIMMs.