Enable core parking to safe precious battery life

This will allow windows to park cores dynamically, which (hopefully) translates into precious mWh saved.

• Open regedit
• Search for the data 'unparked cores' (or just find the key below)
• Keep searching until you get to the following key (in CurrentControlSet).
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\0cc5b647-c1df-4637-891a-dec35c318583
• Find the value "Attributes" and rename it to "Attributes.off" (this doesn't actually do anything apart from preventing windows from finding the real key... and it gives you a rollback path).
• Now search for the term 'unparked cores' and you should end up on the following key
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\ea062031-0e34-4ff1-9b6d-eb1059334028
• Again, find the value "Attributes" and rename it to "Attributes.off"
• Reboot

The key allows to change the minimum number of parked cores, while the second one allows to set the maximum number of parked cores.
Now you can go to Control Panel -> Power Options and edit the power profile. You'll find two new entries under Processor power management.