Please note that I/OAT is part of a NIC feature and VT-C is the technology that provides support for I/OAT. Therefore, any processor that supports VT-D, supports VT-C and by addition I/OAT.
Also, I/OAT is a combination of NIC+Chipset+CPU support. If you want to know if the chipset on the board supports I/OAT, the board should have an option in the BIOS to enable it.
Basically, the NIC card should support it, the motherboard should have the option in the BIOS and the processor should support VT-D.
The Intel® Xeon Processor E3-1275 v2 does support VT-D and this can be confirmed at: http://ark.intel.com/products/65726/Intel-Xeon-Processor-E3-1275-v2-8M-Cache-3_50-GHz?q=E3-1275%20v2