I have the WiFi A version and my slower boot issues are with the sound driver not loading for almost ten seconds on boot.
Try this, remove sound driver with DDU then remove all Realtek and volute drivers form the store using the Driver store Explorer HERE. Reboot. You should see USB 2.0 as sound. Time your boot and post results.
I submitted a ticket to Asus. They are investigating.
Samsung 980 has no driver. You have to use MS default driver.