Asus Maximus IV GENE-Z - Manual (Page 85)

2.5 Turning off the computer
While the system is ON, pressing the power switch for less than four seconds
puts the system on sleep mode or soft-off mode, depending on the BIOS setting.
Pressing the power switch for more than four seconds lets the system enter the
soft-off mode regardless of the BIOS setting. Refer to section 3.7 Power Menu for
details.
ASUS Maximus IV GENE-Z 2-53