Arria 10 development board not recognized correctly via PCIe connection to PC

Hie Frank, It is not expected that Arria 10 development kit to show device cannot recognized across multiple motherboards. I will suggest to first try to replace your design with Example design generated by Quartus Prime Pro using Avalon ST for Gen2x8 configuration. Then, please install the included Quartus feature driver and check if your motherboard can recognize the device. If this shows the device can be recognized, then i will primarily suspect your design. Please compare the Example Design generated by Quartus and your design. Please refer to following document on generating Example Design using Quartus: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/ug/ug-dex-a10-pcie-avst.pdf If Quartus Generated design still fails, then we need to debug what is causing the failure. We need to first determine if the Pysical Layer can achieve L0. Please signaltap the LTSSM state and let me know. I can help analyze and advice accordingly. Hope, my reply gives you some guidance on how to debug your issue. Regards, Nathan