When encoding with HandBrake we saw a 2fps difference between the slowest and fastest of the X79 boards. At the top of the heap was the Gigabyte G1.Assasin 2 followed by the Asrock X79 Extreme9. Then at the bottom was the MSI X79A-GD65(8D) which was slower than the Asus P9X79 Deluxe.
The x264 HD Benchmark 4.0 saw a 5fps difference in the first pass test between the fastest and slowest X79 boards. The MSI X79A-GD65(8D) was again the slowest X79 board, with the ECS X79R-AX taking the lead delivering 175.4fps.
TMPGEnc 4.0 XPress saw the six X79 boards deliver virtually the same performance as they all completed the task in around 5 minutes and 30 seconds.