Looking at prior data
A9, iPhone 6s → 2315
A9X, iPad Pro 2016 → 2955 (1.28×)
A10, iPhone 7 → 3325 (1.12×)
I’m gonna go out on a limb here and estimate that the A11 will be…
A10, iPhone 7 → 3325
A10X, iPad Pro 2017 → 3930 (1.18×)
A11, iPhone 8 → 4422 (1.12×)
4422 puts the A11 at i7-4770k performance levels. 🔥
Conservatively going with 1.18× that means the next iPad Pro based on A11X will be 5218 which is above the i7-6600k and within a beat of the i7-6700k.
It’s already sketchy with A10X today, but at that point in 2018, I don’t even know why Apple would continue to bother with Intel chips at all.
(These estimates might be too optimistic though, as @jsnell pointed out in another topic. I am very very curious to see what the actual A11 numbers look like when iPhone 8 is released.)