Asus Sabertooth 55i - Manual (Page 60)

2-40 Chapter 2: Hardware information
Chapter 2
2.9 Onboard LEDs
POST State LEDs
POST State LEDs check key components (CPU, DRAM, VGA card, and HDD) in
sequence during motherboard booting process. 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.
You may disable the POST State LEDs in BIOS. Refer to section 3.8.2 Boot Settings
Configuration for details.