Are you booting off the RAID? If so, you may want to stick with WD Black since it is the performance drive. Although, Black drives aren’t really designed for RAID environments, I’ve saw other users have Black drives in a small RAID1 or RAID0 like you have without any issues. I personally use two VelociRaptors in RAID1. They are designed for RAID use and at 10,000rpm I get pretty good performance out of them.
WD Red’s are recommended for RAID use and should be fine if you are using them for storage and not a boot volume.
