In our Sandra and Everest testing, the difference in score certainly is because of the DDR3 frequency. The ASRock board scores a good deal less because of it. POV Real Time and Beta were also tests that were found to favor the higher DDR3 speeds on the Intel board. Cinebench 10 showed the ASRock X558 SuperComputer to be 3 seconds slower in rendering.
HDTach was a split between the two boards with the ASRock board doing better in the burst testing and the Intel board scoring better in the average test. The Intel board also rose above the ASRock in three of the four 3dMark 06 scores.
Our gaming tests all seemed to favor the ASRock board, and it outscored the Intel considerably in the Lightsmark 2008 testing. It also scored better in the Call of Duty 4, Company of Heroes testing. The two boards tied in F.E.A.R. and Vantage testing.
Both boards did very well. It would have been nice to see how the ASRock board would have scored if it were able to run at the same DDR3 speeds.