Thanks Michael_P, - not sure if the logs showed this but I'm using an older GA-X99-UD5 system board to support a used Intel Xeon CPU E5-2690 v3 that I had laying around, I'm a version off the latest available BIOS (2018), with said version showing only 'CPU Microcode' updates. I'm not sure it's worth the risk without a newer system board and possible CPU ready to go. The fact that I recently installed a GTX 5070 using the latest open source driver v580.95.05 to support it tells me that its probably the PCIE gen as you say and a newer system board will be required to resolve. Thanks again for the quick response and great diagnosis!