I think RR could be bad seed here as it tends to give you dropped frames.
Ask Bob Zelin on SAN forum here on cows.
For test populate all available bays with empty drives, lets say 2 tb ones.
Stripe them together and use it to playback something.
You should get some 300 MB sec with 3 drives.
If it plays nicely then RR is bad by design or by unit.
—
Margus
https://iconstudios.eu