2. Navigate to "HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Power\PowerSettings\0012ee47-9041-4b5d-9b77-535fba8b1442\0b2d69d7-a2a1-449c-9680-f91c70521c60".
3. Change value "Attributes" to 2. At this step you won't have modified ANY functionality in Windows (except for a tiny detail in the power management USER interface), so it's 100% safe.
4. Reboot.
5. Now go to "Power Management" in Control Panel and click "Change plan settings" of your power plan, then click "Change advanced power settings".
6. Expand the "Hard Disk" settings tree. You'll see that now there is and ADDITIONAL setting: "AHCI Link Power Management - HIPM/DIPM". Expand this one.
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The default power setting for Balanced about ALPM (AC,DC).
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\0012ee47-9041-4b5d-9b77-535fba8b1442\0b2d69d7-a2a1-449c-9680-f91c70521c60\DefaultPowerSchemeValues\381b4222-f694-41f0-9685-ff5bb260df2e]
"ACSettingIndex"=dword:00000001
"DCSettingIndex"=dword:00000001
Some information is in the http://msdn.microsoft.com/en-us/library/windows/hardware/gg463243.aspx
