Samsung's Exynos 8890-based Galaxy S7 is the slower of the two chip models, and that's the European model
It appears that Samsung has switched tactics for the Galaxy S7 and Galaxy S7 edge. In previous years, Samsung regularly produced variants of its flagship range, including the previous-gen Galaxy S6 and Galaxy S6 edge, using both its own Exynos processor and Qualcomm's Snaprdragon chips.
In these past cases, the Exynos chip has usually proven faster, and has been inside Galaxy S models distributed in Asia, Samsung's home market. Meanwhile, everywhere else, including the UK, Europe, and North America (USA and Canada), recevied the Qualcomm Snapdragon-powered models, which were a little slower according to benchmark tests.
Now though, the wind has changed. According to a report from the Telegraph, which cites multiple benchmark tests, the Snapdragon 820-based Galaxy S7 and Galaxy S7 edge are faster than both Apple's current-gen iPhone 6s and iPhone 6s Plus, AND the Exynos 8890 based Galaxy S7 and Galaxy S7 edge models. BUT, and here's the kicker, Samsung has allegedly, at least according to this report, swapped the distribution round, so now only the Asian market is getting the Qualcomm Snapdragon models, while in Europe and the UK we have the Exynos-based edition with slightly slower performance.
Again though, the performance difference is shown in benchmarks, and it's a fairly small gap, but it's there nonetheless. More dramatic is the difference between GPU performance for graphics with both the iPhone and Exynos-based Galaxy S7 trailing quite far behind Samsung's Qualcomm-based model.