Adding RAID 0 disks to a system previously setup as AHCI
Thank you @user1686 - I figured it out.
- connect the new disks
- set motherboard to RAID in bios
- install AMD RAID drivers and s/w in Windows (<-- had to happen after 2. above otherwise would not install correctly)
- setup RAID array in AMD s/w in Windows
- initialise and format new disks in Disk Management
- go to superuser and post the answer