Is 100/200 Mb/s normal?

@chrisle 

Any chance you have Disk Warrior? (to optimize the volume directory)

I assume if you run Activity Monitor (Utilities folder), click on the disk tab, then go to SoftRAID, and verify disk for 2-3 minutes each (the tab shows the throughput on bottom), that you get 200MB/s on all 4 disks? (you can cancel in SoftRAID utilities menu)
What if you validate volume? What approximate throughput do you get?