Like many of you I have been trying to make my older machines break into the newer era of Windows. One major hurtle is the EFI32 on all of the first generation Intel macs that makes installing Windows x64 on them nearly impossible. .
See my thread. i successfully installed windows 10 on my mac pro 1.1/2.1
Native Install Windows 10 on mac pro 1.1 / 2.1 without usb or dvd or bootcamp