Quite simple. Telemetry, telemetry and again telemetry... Everywhere + rubbish left from the old patches. I would say 80% blame goes for telemetry... 20% for thousands of rubbish files Windows had created if installed few years ago.
1. Deal with NVidia massive telemetry scans started at each boot = Uninstall Geforce Experience = completely. It’s insane how much this one thing is slowing the boot time!
2. Use Autoruns by Sysinternals - look for all NVidia entries that have telemetry and untick them. Leave only NVDisplay.ContainerLocalSystem ticked.
3. Now deal with MS rubbish. Open Regedit.exe and go to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Miscrosoft\Windows\DataCollection and create or change if existing DWORD key named "AllowTelemetry" to value 0.
4. Check your Antivirus software for boot/logon scans and reduce its scope if possible.
5. Clean your Windows by using:
a. PatchCleaner by
http://www.homedev.com.au/ b. Perform disk cleanup – right click over C: drive – General – Disk cleanup button – make sure to switch to admin mode to delete Windows update files.
c. Delete old, unused drivers using DriveStoreExplorer – also use admin mode.
6. Reboot.
And ENJOY!
🙂 Hope it helps.