There is none. No card "requires" an i7 or even an i5 for that matter. That being said, there is a matter putting together a "balanced" build and if there's budget enough for a 1070, I would expect the CPU to be a 7600k or better.
What do you mean? I'm not understanding this question. Any i5 or i7 will use a 1070. I'd say i7 just because of hyperthreading a long with overall a future proof.
There is none. No card "requires" an i7 or even an i5 for that matter. That being said, there is a matter putting together a "balanced" build and if there's budget enough for a 1070, I would expect the CPU to be a 7600k or better.