RE kozzy30320111…
Your issue could be a non-enabled / not present / defective battery for the write cache.
I deal just with HP Servers. They have the SmartArray P212/P410 or new P222/P420 as the default RAID Controllers.
When the Battery or Flash Write Cache (BBWC or FBWC) is disabled, defective or not present, I have an upload ratio to the ESXi Datastore of 3 MByte/Sec.
An direct to the on-board SATA Controller attached SATA-HDD over 60MByte/sec.
When adding the Battery to the RAID Card - all went fine.
Upload normally over 80MByte/sec on big files to the Datastore wich resides on the RAID Controller.
Regards,
Josip.