I would say go with the H100i.
They're both great coolers, but the H100i gives you a little bit more headroom by the ability to add up to 4 fans in a Push/Pull setup. Of which, you will probably need for that kind of clock.
5GHz is quite the target though, even with the right cooler you'll have to have a pretty decent chip for that. The 4790k already runs fairly warm given its stock frequency.
I wish you luck, I'd love to see some benchmarks on what that chip can handle at 5GHz if you can achieve it!