The RS25CB080 controller uses the LSI* SAS2208 ROC controller and supports RAID levels 6 and 60.
See the Usability section on page 13 of the Intel Integrated RAID Module RMS25PB080, RMS25PB040, RMS25CB080 and RMS25CB040 Hardware User's Guide.
The difference between the PB and CB controllers is the PB controllers are a standard adapter where the CB controllers are modules to connnect to a propritary server board connector.
The ESRT2 onboard RAID controller does not support RAID levels 6 or 60. Or RAID 5 without an enabling key.