Not only all the updates but non-Microsoft drivers to get it working.

http://www.gigabyte.com/products/product-page.aspx?pid=4739#dl shows no XP drivers so that's not interference but something else altogether.

What do you mean Windows 8.1 "mode"? Most folk write "when I boot Windows 8.1."

Most of what I see today is that today's owners are having to catch up on drivers and app installs. That is, many will install Windows, and hope it all works.
Bob