Dear Josue
You may have already seen the benchmarks at https://www.notebookcheck.net/Microsoft-Surface... - they also took into account the performance on benchmarks after the tests were run several times to account for power throttling. Josher14 is another surface pro user who posts gaming benchmarks on YouTube that is a good indicator of how they perform under sustained gpu/cpu load.
Essentially, both i5 and i7 will power throttle, but i7 is still significantly more powerful than the i5 after that. Both are suitable for office work, but you may prefer the stronger integrated GPU in the i7 for Adobe applications. May I have more details about how you plan to use the tablets?