For maximum performance, you need to set the “Read Prefetch” to 8 stripes (512 MB per disk), also enable Apple Drive Module (ADM) Drive Cache and Write caches.
Disable “Use Steady Streaming Mode” may give you better performance too.
To compare the speed, if you google online, you may fine an interesting aricle about Xserve RAID vs. Caldigit HDPro:
https://www.geekymac.com/?p=528
it should cover everything you want to know.