For 1080p, gtx 1070 should be enough for next 3 years. So for pure gaming, both those setups are equal for you. But if you want to stream while playing, hyper-threading of 8700 will come very helpful, so I would advise 8700+1070 setup. Actually, look around if you can't find some 1070ti at similar price as 1070, because 8700+1070ti would be sweet spot for you.