How do I see what's taking so long during the "Starting Windows"?

How do I see what's taking so long during the "Starting Windows"?

Sometimes my computer takes several minutes to start (that is "Starting Windows" displays for several minutes) and other times it starts quickly. It seems to be almost arbitrary. I have read USB devices could cause it but I only have a USB keyboard connected. I also read that I could disable the "Starting Windows" graphic on startup so I enabled "No GUI boot" and "Boot log" in msconfig. Unfortunately that didn't tell me very much. The No GUI boot just shows the "bitlocker key loaded" message the entire time instead, and the boot log does not show how long it takes to load each driver.

Anything else I could try?

It is possible that there is a service that loads when you start Windows, and that it sometimes takes a long time to fully load, thereby slowing everything down.

To see if this is the case, run MSCONFIG and go to the services tab. Check the box which says to hide the Microsoft services. Once you have done that, the only services you will see are the non-Microsoft services. Disable them all, then restart the computer. Now see if the problem has disappeared.

If the problem has disappeared, then it was caused by one or more of the non-Microsoft services.

To re-enable all services except for the one or two which were causing the problem:
Go back into MSCONFIG and go to the services tab.
Re-enable one service, then reboot. See if the problem has returned. If not, re-enable one more service, reboot again. Keep doing this till you find which one was causing the problem, then disable that service in MSCONFIG.

Continue re-enabling one service at a time, till they are all re-enabled, except for any that you find which are causing problems.

The problem is it seems to be arbitrary and I just don't think that's going to give me an accurate reading. Is there any way I can watch on the screen what it's doing as it's booting, like in linux you can do that on boot and if something is slowing things down you can see what it is.