Hi, sorry it's not possible, You can't use without RAID.
I have an R620 PowerEdge server with was giving an error message PCIe Training Error Integrated Raid  System Halted  After removing the Raid controller everything was fine it was booting. Now I m trying to load the operating system but it is failing to detect the single SATA hard drive I have put in the slot. The LEDs for the harddrive are not switching on also. Can someone tell does the server work without the raid controller if so how do I go about ensuring that it reads the SATA hard drive  
R620 without Raid Controller