Aggressive Link Power Management (ALPM)

AHCI Link Power Management

AHCI Link Power Management is a technique where the SATA AHCI controller puts the SATA link to the internal HDD and/or SSD disk into a very low power mode when there's no IO (input/output) activity for a while. The controller automatically puts the link back into active power state when there's real work to be done. This is done to save power consumption by the HDD and/or SSD disk.

• HIPM = Host Initiated Link Power Management
• DIPM = Device Initiated Link Power Management

Windows

The Link Power Management option is default in the Advanced Power option of Windows:

1. Adding the AHCI Link Power Management – HIPM/DIPM option to Advanced Power Settings.
   1. Download the Add_LPM.reg file.
   2. Right click on the downloaded .reg file and click on Merge.
   3. After the success message appears, restart the unit.
2. Removing the AHCI Link Power Management – HIPM/DIPM option from Advanced Power Settings.
   1. Download the Remove_LPM.reg file.
   2. Right click on the downloaded .reg file and click on Merge.
   3. After the success message appears, restart the unit.
3. Configuring the AHCI Link Power Management – HIPM/DIPM option in the Advanced Power Settings.
   1. Click on the Start button.
   2. Type Power Options in the Start search box and press Enter.
   3. In the Power options window, click on the Change plan settings of the current power plan.
   4. In the Plan Settings window, click on the Change advanced power settings.
   5. In the Advanced Plan Settings click on the Hard disk option and expand it.
   6. The following settings are responsible on the AHCI Link Power Management:

• AHCI Link Power Management – HIPM/DIPM. It will set the Link Power Management policy:
  • Active: Neither HIPM or DIPM allowed
  • HIPM: HIPM only is allowed
  • HIPM+DIPM:HIPM and DIPM are allowed
  • DIPM: DIPM only is allowed
  • Lowest:HIPM, DIPM and DEVSLP are allowed (if DEVSLP is supported by the storage device).
• AHCI Link Power Management – Adaptive. It will set the period of AHCI link idle time before the link is put in the slumber state when you have HIPM, DIPM, HIPM+DIPM or Lowest set above. It can be set to be from 0 to 300,000 milliseconds. If the Active is set above, then this will have no effect.