Assuming same GPU and RAM, with different CPU, Benchmarks vary...

[MeoTwister5]

So I did some research to see how much CPUs would seem to affect the benchmark scores assuming same GPUs and RAM.

Since I have a 1070 and 4 year old i5 Haswell, I compared my scores from those I could see here and in reddit with the same GPU and RAM as me.

I'm seeing variations everywhere from 9500 to 15000, which seems like a large range for just a difference in CPU. Generally speaking:

9000ish range - Older AMDs and older i3s.
12000ish range - i5 Haswells, and it seems some older model i7s.
14000-15000 - The i5 to i7 Sandy Bridges and the few Skylakes I could see sit comfortably here.

I haven't seen Kaby's and Ryzens yet.

[Lozza]

Honestly this isn't all that surprising, many MMORPGs are CPU bound, consequently a better more efficient CPU will result in a better performance.

[Culfinrandir]

FFXIV has always been a CPU hungry beast. Unfortunately it doesn't seem to make efficient (if any, haven't checked for a while) use of multiple cores or threads. If it begins to do so, & implements decent multi-gpu support, it will be a different situation altogether & so much smoother.

[Akira]

kaby lake isnt much faster then skylake actually so should see similar results. in fact there even at the same clocks so you could say the 7700k is just a 6700k with higher stock clock