Question: How do I turn off USB port power under S5 mode? (7/1/2017) Answer: USB port power can be turned off by enabling "Deep Sleep” option.
Please press "F2” or "Del” during POST to enter BIOS setup, select the "Advanced” menu and enter the "Chipset Configuration” page, and adjust the "Deep Sleep” option to "Enabled in S5”.
After adjusting the setting, press "F10” to save the configuration. Then USB port power will be turned off under S5 mode.