Hey philipma1957
I noticed that you bought the Taichi x399 board, I bought a few of the same boards with a 1900x TR and I have been having a very hard time trying to get a M.2 to pcie 4x adapter working in any M.2 slot. (testing with a 750ti)
I'm running windows 10 and I have tried several types of powered risers and cables, tried swapping the cpu to another 1900x, swapping motherboard to another x399 asrock taichi, swapping ram, tried every bios available, a few other nvidia drivers, swapping the graphics card.
and still no luck.
Its got me stumped.
I have gotten the card to work, randomly but It will always crash or freeze and reset the driver, on a few occasions I have had the card working and hashing for 2 hours even and I think I have got it and it will freeze or I will reboot and the card will not be detected.
has to be one of the hardest things to get working with this board. It seems that it will not run a gpu off the m2 slot via a adapter. I'm thinking its a bios issue, not sure what to try next.
Have you tried a M.2 to pcie x4 adapter on your x399 taichi mobo ?