At stock clocks my i5 only achieved scores around 13000 and that was paired with the 1080. However at an overclock to 4.5GHz the score increased to 17000.

The engine clearly responds well to higher clock speeds than anything your GPU is doing. I imagine a 1070 paired with a decently overclocked i7 could get around 17000 as well.

Solution: Overclock if you really want more performance in FFXIV