Cpu can't bottleneck a gpu. Cpu sets the maximum fps. The gpu has to live upto that number according to resolution and detail settings. If the gpu is strong enough, it'll put up on screen everything the cpu gives it. If the gpu is weak, it'll only put up what it can, lowering detail settings will help raise that some. But no matter what, nothing a gpu does will ever make the fps limit given by the cpu go Up. The gpu gets what it gets.
You could put an RTX2080ti with that i5, doesn't mean that the cpu will slow the gpu down, just means the gpu is more than capable of putting up on the screen everything the i5 gives it, at any detail setting or resolution.
Pair that i5 with a GT710, and now you have a bottleneck since the gpu cannot put up on screen anything close to the amount of fps the cpu gives it, at any detail setting or resolution.
In most cases, the major source of any bottleneck is the game code itself. CSGO, 2 threads, no worries at 200-250fps. Gta:V, 8 thread optimized, different story on a quad, it's going to take a good sized hit. Assassin's Creed, any of the Uplay crap. Good luck there, they are so badly optimized you need serious horsepower in the pc to get decent results.
Gpu doesn't affect cpu fps limits. Game code does. And that includes things like scripted mods for fallout or skyrim or even minecraft.