Hello Olivier,
Thank you for the update.
I appreciate your efforts and concern.
As boot time is lesser and Windows is taking longer to shutdown before restart, please refer suggestions from
apster replied on February 24, 2010 and check if it helps.
Note: Serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
https://support.microsoft.com/en-us/kb/322756
Please keep us posted.
Thank you