Question about Corsair H100i v2

this cooling will be enough for sure but it is not 100% sure if the 7700k can do 4.7ghz.(at least at usable temps) i can't say about the grad c because i don't own either. also the 7700k can be overclocked differently if you get a better chip you can overclock higher or overclock at lower temps/power consumption. then it is also important whether you head the cpu or not. also relevant is what you use for a heat-conducting paste or what you set for a fan characteristic curve. my statement is: your question is much too relative to get a reasonable answer.

A colleague of mine has the i7 8700k at 4.9Ghz at around 70 degrees, so that should be enough.