Mac Pro Late 2013 AMD FirePro D700 D300 D500 Windows 10 Boot Camp Driver

More than a question this is an advice, if you are running Windows on a Mac Pro Late 2013 (the so called "ash tray") and you want to upgrade to Windows 10 you will have some problems ONLY with the video cards, at this moment (Monday, July 27, 2015) the AMD Boot Camp drivers downloaded with the Boot Camps assistant on OS X are NOT working at all with Windows 10, also, the drivers available directly from the AMD site are buggy on Windows 8.1 and don't work at all in Windows 10.

http://support.amd.com/en-us/download/desktop/bootcamp

After realizing that the video cards didn't work I had to rollback (downgrade) to Windows 8.1 and I'm amazed that is quite easy and very fast, here is a video showing how:

https://youtu.be/UIj1H_6R7-k

So you have been warned, wait until Apple release the Windows 10 Boot Camp drivers.