In early results, it's a split decision. The S7 with the Exynos 8890 wins the multi-core test with a score of 5,946 against the Snapdragon 820 S7's 4,979.
However, when it comes to the single-core test, the Snapdragon scores 2,282 and the Exynos scores 1,873.
Again, these are early examples, and final S7 hardware should see improvements for the Snapdragon model.
But it seems as if Samsung is pursuing the flashier multi-core performance crown, which relates to extremely high-end tasks like gaming.