A detailed comparison by Anandtech between the Galaxy S8 Exynos 8895 and the Galaxy S8 Snapdragon 835 showed a performance difference between the two SoC. While both chips traded blows and the difference didn't seem as pronounced, ultimately the Snapdragon 835 offered better performance.
https://www.notebookcheck.net/Samsung-Galaxy-S8-Exynos-8895-vs-Snapdragon-835-performance-comparison.237762.0.html