I don't know much about servers, but isn't 2x i7-2600 potentially a better solution than 1x 3930k?
Split the servers among 2 machines and you get 8 core / 16T @ 3.4 GHz for 2 i7-2600 for the same price as 6 core / 12T @ 3.2 GHz for the 3930k.
Memory bandwidth is half, but you're buying the same amount of RAM. 2x H67 boards are about the same price as 1 X79 board. I don't know how either compares to an opteron, but certainly 8 faster SB cores is going to work better than 6 slower SB cores.