Calaudude wrote:you cant use SSD as RAID
only use SSD as single drives
IIRC, with SATA ports from Intel's c206 chipset, along with 2012/3 version of Intel's iRST drivers, 2x SSD in RAID 0 was supported and TRIM works as it should. For SSD's in RAID1, i'm not sure what the state was.
Note that Intel has droped support for the c206 chipset from later drivers, so one need to check the latest iRST driver actually supports their workstation chipset AND supports SSD's in RAID 0 & 1, etc.
I'd be surprised if the c602 chipset as used in the Z820 workstation had less capabilities (w.r.t. SSD RAID via iRST) than the c206 chipset as used in my Z210 workstation 
As for the LSI integrated SAS contoller on the Z820 mobo, i'm not sure what RAID level support exists for SAS SSD's and whether TRIM is also supported but i can't see why it should be less featured than iRST (other than purposely hobbling the drivers to sell fully featured PCIe RAID solution).
So if you have some information on why you can't use SSD's in RAID on a Z820 workstation, please post a link to a reference as it's more helpfull than a one liner 