Hi Phil, I put windows on the Onda B250 you sent me this past Sunday.  I played around a lot changing bios settings, got a black and then a grey screen.  I was connected to an Nvidia card, not to the internal GPU.  I was also connected to the network.  I ended up hitting the clear CMOS button by the 2 USB ports.  That at least got me to the screen where I could enter the bios settings again.  This time I think I only changed PCIe speeds from max to Gen1.  Rebooted, loaded windows from a USB stick, install went fine.   I'll check over the weekend, but I am pretty sure I did not enable the 4G option, which you have to do on Asus Z270 boards.  Can check all the other settings as well and I will report back.

But bottom line, same exact board and Windows is running fine.  For memory I used the G.Skills stick that either you or someone else on here posted the link to NewEgg.