Intel Motherboards - How do I kill USB port power when system is off?

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How do I kill USB port power when system is off?

Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=2910
Printed Date: 19 Jul 2025 at 5:57am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: How do I kill USB port power when system is off?

Posted By: djrandolfs12
Subject: How do I kill USB port power when system is off?
Date Posted: 23 Jun 2016 at 9:38pm

I have a USB mouse and keyboard who's LEDs stay illuminated even when system is shut down. They don't have any software or drivers i can go in and manually adjust this. If i want the lights off i have to manual shut off the PC from the power supply which is quite frustrating. Anyone know if there is a way i can kill the power in shut down in the BIOS or something? Any searches I've attempted have yield no results :( I have an ASRock Z-170 PRO4S.

Replies:

Posted By: Boltar
Date Posted: 23 Jun 2016 at 10:58pm

The PSU will generally leave the 5V rail energised regardless of the state the motherboard is in, it does this because the board needs power to detect the momentary button being pressed to turn it on (as well as other things like not depleting the CMOS battery). So unless the board has special mosfet circuitry to the USB ports to switch the power (most don't) you're out of luck. There are some powered USB hubs that will do this, but they are very specific (usually ones that have a power button on them). In that when they sense their host is offline, they shut off power to the hub ports.

It is odd that the LEDs stay on on these devices as they usually have the ability to detect the host is offline and go into shutdown.

As a test, I would try going into the Bios/Uefi and finding any options regarding waking up or powering on via the mouse or keyboard and disabling them. See if that helps.