Asus P9X79 LE - Manual (Page 38)

2-20 Chapter 2: Hardware information
Chapter 2
3. FLBK LED
The FLBK LED lights up when the USB Flashback switch is pressed for three seconds.
2. Q-LEDs
These ID LEDs of CPU, DRAM, VGA card, and HDD indicate key component status
during POST (Power-on Self Test), providing an elegant embellishment to the
motherboard design. The LED lights will flash sequentially during system bootup. If an
error is found, the LED next to the error device will continue lighting until the problem is
solved. This user-friendly design provides an intuitional way to locate the root problem
within a second.