I think the card might only support up to 2TB - I looked at the tested list at http://www.intel.com/support/motherboards/server/srcsasph16i/sb/CS-028825.htm, and there's nothing bigger than 2TB listed.
I figured that might well be the case. Would it be worthwhile (and how would I) making contact with Intel directly to see if that actually is the case?
I wonder what the chances are of Intel creating an updated firmware version that brings the card up to current drive tech?
The SRCSASPH16I uses the LSI Logic* SAS 1068 eight-port controller. The LSI 1068 has a hardware limitation at 2TB, there is no way around it. The 1078 or 2108 ROC chips or 2008 SAS chip will support disk capacities well above 2TB.
Looks like I might have to be upgrading a lot sooner than I anticipated.