Originally Posted by
Greypaw
There you are - both SSDs remember they're part of a RAID1, but you're new Board doesn't so the info which Windows8 installer is getting from your BIOS is only one SSD (shown on your Screenshot) and this(the SDD) says "No, you're not allowed to install anything on me cause I'm part of a RAID1"
Refering to the Manual (sorry I'm not allowed to post Hyperlinks in lack of postings...): Page 3-55 you've to reconfigure both SSDs to RAID1 again and then you should be able to install Windows on it.
Or deactivate the RAID1 and install your OS on one of them.