Win 10 annoying slow start issue, black screen between boot and login screen HELP!

I upgraded my (pretty new) windows 8.1 installation to Windows 10.

But ever since i did that i get a very annoying issue.
When starting, restarting or getting out of sleep.
i get the hp logo for a second then windows logo (spinning dots) for about 8 seconds and then the screen goes black?! NO MOUSE CURSOR either, for over a minute! and after that i can login (enter password) and when logged in everything is fast and responsive

I have no idea how to solve this.
on windows 8.1 i had the same problem but only for a week or so (and it starting within 15 secs) (and i-am running win 10 for several weeks now)
how can i see what hangs?

Does anyone have the golden tip?

on a HP dv6-6b50ed

[EDIT] i uninstalled the AMD driver restarted a couple of times and it boots within 15seconds... after that i reinstalled 17.1 driver and i got the same F ing bs [/EDIT]

[EDIT2] I installed AMD 15.6 beta driver and issue seems to be resolved (grabbed it from leshcat, and no the 15.7 leshcat drivers did not work) hopefully the next driver update will fix the issue [/EDIT2]