If one agrees, that at certain resolution X, the difference is say 15-20%, and tomorrow with more powerful GPUs the difference will move to resolution X+1I am really tired of this gaming discussion.
Difference in this workload scenario is so negligible that people are arguing over height of graph bars.
I'll tell you, if you can indentify system in double blind test in HU 30 or so games benchmark testbed when using appropriate resolutions and game settings to hardware in systems, I'll lick yours pet behind, tape it and upload it to YouTube.
then at certain point it will beome clear that said 15-20% is sometimes more than a step in GPU vendor cards ( like 2070 super => 2080 ).
Just food for thought in "FPS" department.
And FPS is not end to all, there are turn times, simulation speeds, emulation speeds and so on. In the end faster CPU is faster.
P.S. And i also own 3950x, not for gaming tho.