Asus P8Z77 WS - Manual (Page 36)

2-14 Chapter 2: Hardware information
Chapter 2
2.2.6 Onboard LEDs
1. POST State LEDs
The POST State LEDs of CPU, DRAM, VGA card, and HDD indicate key components
status during POST (Power-on Self Test). 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.
2. TPU LED
The TPU LED lights when the TPU switch is turned to
Enable.