So, I did not need to take the motherboard out! The GPU is detected just fine with the BIOS configured to *not* bifurcate the x16 slot and the GPU in either of the two riser slots. Windows 10 installed on the SSD using UEFI, BIOS updated to the latest, latest drivers installed for both the Zotac GTX 1070 and Mellanox ConnectX-4 Lx. Loaded the XMP profile and the RAM is happily up at 3200 rates.
Using Ryzen Master and HWINFO I've done some checkouts and the CPU's not cooking itself. No point saying much about thermals (47C idle, 75C fully loaded for 60 seconds) since the case is still open, cables everywhere, etc and I haven't done real checks.
However, I can only get the GPU to work in Windows when *either*:
1) GPU in either riser slot, Motherboard set to x16 (non-bifurcation)
2) GPU in first riser slot, Motherboard set to x8x8 bifurcation
The GPU does function to display the BIOS in all PCIe configurations. I'm not sure how to even start debugging this issue so I'm posting here and then off to read up more. Any advice very welcome.
Using Ryzen Master and HWINFO I've done some checkouts and the CPU's not cooking itself. No point saying much about thermals (47C idle, 75C fully loaded for 60 seconds) since the case is still open, cables everywhere, etc and I haven't done real checks.
However, I can only get the GPU to work in Windows when *either*:
1) GPU in either riser slot, Motherboard set to x16 (non-bifurcation)
2) GPU in first riser slot, Motherboard set to x8x8 bifurcation
The GPU does function to display the BIOS in all PCIe configurations. I'm not sure how to even start debugging this issue so I'm posting here and then off to read up more. Any advice very welcome.