If it's not displayed under (Advanced/System Agent Configuration), have you checked that Intel Virtualization Technology is enabled under (Advanced/CPU Configuration)?
I have both the i7 4930k and the Rampage IV Formula w/ bios version 4901 (previously 4601), and I can confirm that Intel (R) VT-d is displayed and working (on Ubuntu 14.04 & CentOS 7 w/ KVM :3).