Update : Windows updated the Intel Management Engine Interface right now, it seems that I gained 1 minute in boot time.
Update 2 : After setting the time for Intel AMT to 1 in the BIOS, fast boot again, with desktop in 25 seconds in total.
Anyone can explain what happens with Intel AMT (unless it is a coincidence) ?
Thanks to all anyway.
UPDATE 3 : wrong, boot time more than two minutes again...