Well.
Actually, I already did that once.
When Fall Creators Update appeared, I upgraded, and the freezes started.
I was actually thinking it had to do with something with old installation plus new installation thing.
Turns out I rolled back to 1703 and it was solid again. But many things were not working anymore.
FLAC and MP3 thumbnails not working. Folder icons having black background.
I already had problems like this in 1703, and because it became really annoying, I thought going totally clean w/ 1709.
It turns out this build has this bug, even with all up-to-date patches and updates applied.
Must be something related to the GPU or AMD processor (FX 8320-E) here.
This is a AMD white-box GA-990XA-UD3 with 8GB RAM with the processor above and a GT630 GPU.
I have a Lenovo notebook which had no problems at all with 1709.
So it could be very well the case of being "Fast Start Up" issue.