Dear AMD, community,
It is widely known in the community by this time that the Vega cards have driver issues when used under Windows 10 on an older platform like X58 or Z68, specifically (but not limited to) Gigabyte brand boards.
I too suffer from it as my recently purchased Vega64 will not install on my Gigabyte GA-X58A-UD7 under Windows 10. This forced me to downgrade my OS to Windows 7/8 and thus no longer have DX12 functionality.
The driver install (no matter which version) will always result in a BSOD. It doesn't matter what card it is, it doesn't matter what Windows 10 version it is, it doesn't matter if it's a clean install or not, those have all been ruled out by the community. So far there is only one success story of a Vega card on an X58 platform under Win10 and that's on an Asus Sabretooth motherboard. But since it's only one it can be considered as unconfirmed still..
I already filed an official support ticket but it was closed rather quickly.
The community (and me in particular) are really desperate. I understand there is only a really small user base for this specific combination, but as loyal AMD fans we kinda hope it would get sorted still somehow
If only you are able to take a brief look at it; install a Vega card on an X58 or Z68 board under Windows 10 to reproduce the issue for root cause analysis, that would mean so much.