Link State Power Management (LSPM) is a power-saving feature primarily used in PCI Express (PCIe) devices. It is designed to reduce power consumption by putting the PCIe link into a lower power state when it is idle. While this feature is more commonly discussed in the context of hardware and firmware, Windows operating systems also provide settings to manage LSPM. This article will guide you through the steps to manage these settings using Windows built-in tools such as Control Panel, PowerShell, and Command Prompt (CMD).

Understanding Link State Power Management

LSPM has two main states:

1. Moderate Power Savings: This state saves power without significantly impacting performance.
2. Maximum Power Savings: This state saves more power but may introduce latency when the device wakes up.

Managing LSPM via Control Panel

1. Open Power Options:

   • Press Win + X and select Power Options.
   • Alternatively, you can navigate to Control Panel -> Hardware and Sound -> Power Options.

2. Change Plan Settings:

   • Click on Change plan settings next to your selected power plan.

3. Advanced Power Settings:

   • Click on Change advanced power settings.
   • In the Power Options dialog, expand the PCI Express category.
   • Expand Link State Power Management.
   • Choose between Off, Moderate power savings, or Maximum power savings.

Managing LSPM via PowerShell

PowerShell provides a more scriptable way to manage power settings, including LSPM.

1. Open PowerShell:

   • Press Win + X and select Windows PowerShell (Admin).

2. Get Current Power Scheme:

   powercfg /query SCHEME_CURRENT SUB_PCIEXPRESS LSPM

3. Set LSPM to Moderate Power Savings:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 1

4. Set LSPM to Maximum Power Savings:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 2

5. Turn Off LSPM:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 0

Managing LSPM via Command Prompt (CMD)

You can also use the Command Prompt to manage LSPM settings.

1. Open Command Prompt:

   • Press Win + X and select Command Prompt (Admin).

2. Get Current Power Scheme:

   powercfg /query SCHEME_CURRENT SUB_PCIEXPRESS LSPM

3. Set LSPM to Moderate Power Savings:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 1

4. Set LSPM to Maximum Power Savings:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 2

5. Turn Off LSPM:

   powercfg /change SCHEME_CURRENT SUB_PCIEXPRESS LSPM 0

Conclusion

Managing Link State Power Management settings in Windows can help you balance power consumption and performance based on your needs. Whether you prefer using the graphical interface provided by the Control Panel or the command-line tools like PowerShell and CMD, Windows offers flexible options to configure these settings.