Power Options - Add or Remove "USB 3 Link Power Mangement"

How to Add or Remove "USB 3 Link Power Mangement" in Power Options in Windows 8


information   Information
What is a link

A USB connection between two USB ports. For example, between your PC and a USB 3.0 device.

  • The downstream port (DS port) of a host or a hub.
  • The upstream port (US port) of an attached device or hub.
A link is a pair of DS and US ports; the ports are known as link partners. Each port has two layers. The physical layer transmits or receives sequences of bytes or other control signals. The logical layer manages the physical layer and ensures smooth flow of information between the link partners. The logical layer is also responsible for any buffering that might be required for the information flow.

U states

As per the USB 2.0 specification, a link enters a low power state (consuming less power than the working state) only when the downstream device enters the suspended state through the Selective Suspend mechanism. The USB 3.0 specification decouples link power states from device power states. The specification defines the LPM feature (see Section C.1 in the specification) that refers to power management of physical and logical layers of a pair of ports that constitute a link. The specification defines four link power states known as U states, from U0 to U3. An active link is in state U0.

After remaining idle for a certain period of time, link partners progressively enter U1 (standby with fast exit) and then U2 (standby with slower exit). After they are idle for sufficient time, software initiates the transition to U3 by sending a command to the DS port link partner.

The steps that are required by software, to send the link to U3, are identical to the steps required for USB 2.0 Selective suspend. The device must enter the suspended state when the link enters U3. As a result, the device is subject to similar restrictions as with USB 2.0 Selective Suspend. To overcome those limitations, the USB 3.0 specification defines U1 and U2 states.

Advantages of U1 and U2

U1 and U2 states are designed to complement Selective Suspend, which can lead to significant power savings. After the software configures the link partners for U1 or U2 transition, the hardware enters the states autonomously without any software intervention. The exit times from U1 and U2 are really fast (from microseconds to a few milliseconds) and have less of an impact on the performance of the devices. This allows for much better power management where links can enter and exit these states even when the device is in use.

For example, a device with isochronous endpoints can put the link to U1 or U2 between service intervals. To save some power, when the device is idle, it can send its upstream link to those states even before Selective Suspend gets invoked. There are no restrictions on how much power the device can draw when the link is in U1 or U2. A device could remain fully powered when the link is in U1 or U2. Therefore, unlike Selective Suspend, a device can send its link to U1 or U2 without losing any capabilities.

For more detailed information, see:


This tutorial will show you how to add or remove the "USB 3 Link Power Mangement" setting under USB settings in Power Options for all users in Windows 8 and 8.1.

This setting specifies a power management policy below to use for USB 3 links when they are idle.

  • Off = Do not enable the U1 U2 states.
  • Minimum power savings = Enable the U1 U2 states, but choose conservative timeout values to optimize for performance.
  • Moderate power savings (default) = Enable the U1 U2 states, and choose optimal timeout values to balance power and performance.
  • Maximum power savings. = Enable the U1 U2 states, and choose aggressive timeout values to optimize for power.

You must be signed in as an administrator to be able to do the steps in this tutorial.

Note   Note
This could be handy if you wanted to set this how you wanted, then remove the setting to prevent other users from being able to change it in Power Options.


EXAMPLE: "USB 3 Link Power Mangement" in Power Options

USB_3_Link_Power_Mangement.png



Here's How:

Note   Note
The .reg files below are for the registry key and value below.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\2a737441-1930-4402-8d77-b2bebba308a3\d4e98f31-5ffe-4ce1-be31-1b38b384c009

Attributes DWORD

1 = Remove
2 = Add



1. Do step 2 or 3 below for what you would like to do.


2. To Remove "USB 3 Link Power Mangement" from Power Options
NOTE: This is the default setting.

A) Click/tap on the Download button below to download the file below, and go to step 4 below.

Remove_USB_3_Link_Power_Mangement.reg

download

3. To Add "USB 3 Link Power Mangement" to Power Options

A) Click/tap on the Download button below to download the file below, and go to step 4 below.

Add_USB_3_Link_Power_Mangement.reg

download

4. Save the .reg file to your desktop.

5. Double click/tap on the downloaded .reg file to merge it.

6. If prompted, click/tap on Run, Yes (UAC), Yes, and OK to approve the merge.

7. When finished, you can delete the downloaded .reg file if you like.



That's it,
Shawn


 

Attachments

  • Add_USB_3_Link_Power_Mangement.reg
    786 bytes · Views: 4,895
  • Remove_USB_3_Link_Power_Mangement.reg
    786 bytes · Views: 2,068
  • USB3_0_Logo.png
    USB3_0_Logo.png
    15.7 KB · Views: 380
Last edited:
Hi Shawn,

My system is Windows 7 with NEC USB 3.0 Host.
But, no link power management added following the steps.
Is it only for Window 8?

416
 

My Computer

System One

  • OS
    Windows 7
Hello Taipei, and welcome to Eight Forums.

Yep, it's only available in Windows 8 and 8.1. :(
 

My Computer

System One

  • OS
    64-bit Windows 10
    Computer type
    PC/Desktop
    System Manufacturer/Model
    Custom self built
    CPU
    Intel i7-8700K OC'd to 5 GHz
    Motherboard
    ASUS ROG Maximus XI Formula Z390
    Memory
    64 GB (4x16GB) G.SKILL TridentZ RGB DDR4 3600 MHz (F4-3600C18D-32GTZR)
    Graphics Card(s)
    ASUS ROG-STRIX-GTX1080TI-O11G-GAMING
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    2 x Samsung Odyssey G7 27"
    Screen Resolution
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    Hard Drives
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    OCZ Series Gold OCZZ1000M 1000W
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    Cooling
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    Internet Speed
    1 Gb/s Download and 35 Mb/s Upload
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    APC SMART-UPS RT 1000 XL - SURT1000XLI,
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Thanks Brink. I added the .reg file and set it to off. I hope it stops my WD USB 3 external HD from going to sleep. I have tried all the other tricks. None worked so far. What's strange is I have 2, one sleeps the other does not.
 

My Computer

System One

  • OS
    Windows 10 Pro 64 bit
    Computer type
    PC/Desktop
    System Manufacturer/Model
    Dell Studio XPS 9100
    CPU
    intel i7 920 @ 2.67 GHz
    Motherboard
    Dell
    Memory
    24 Gig
    Graphics Card(s)
    ATI Radeon HD 5670
    Sound Card
    Internal
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    23" Flat Screen HDMI
    Screen Resolution
    1366 x 768
    Hard Drives
    Samsung EVO 850 250 GB SSD
    2 Seagate internal 1TB
    WD external 3TB USB 3
    WD external 2TB USB 3
    PSU
    550-W
    Case
    Mid
    Cooling
    Fans
    Keyboard
    US USB
    Mouse
    USB
    Internet Speed
    3.84 Mbps Download .44 Mbps Upload
    Browser
    IE11
    Antivirus
    MS Defender
    Other Info
    Liteon DVD wrighter
    Liteon BD drive
    Monoprice Tablet
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