You know? I had a similar issue, though not as extreme when using my Intel Pro 1000/PT PCIE NIC. Windows would not recognize it at all, or it would be listed as a totally wrong device in Device manager etc. It never halted post however. It was particularly bad if I cleared CMOS for whatever reason. This was using the last PCIE 16x slot. The way I got it to work was to actually unplug the power cable from the back of the PSU itself and let the system sit a few minutes then plug it back in. The system will double power up after that but 9/10 times the NIC would come right back up as it should. As long as I didn't do any drastic changes in the CMOS, flash a new bios or have the settings cleared it would stick and be ok. I am not sure if this will help you but hopefully it will. If you are already on the latest bios perhaps this is something that can be looked into for a future release if there is a known compatibility problem to be found. I doubt it, but does the card itself contain a firmware that can perhaps be updated?