I have been working with AMD since the K2 days. I started using RAID 5 starting with Series 7, 8, and 9. All showed the same no matter what board I would use with Windows. Port 4 would always disconnect and send my array into critical. 990fx is no better and makes me want to rethink using AMD. I can run the same boards with Linux or BSD and I don't have the issues. Please fix your drivers!
need to provide the following information on your Current computer setup as per AMD Forum rules: INFORMATION REQUIRED WHEN POSTING A QUESTION .
By any chance are you using a Non-AMD GPU card in your computer and have you tried to update the RAID chipsets to the latest?