As you can see, GTA V is quite CPU bound and this is evident by the performance gains seen when moving from the Core i3 to the Core i5 (around 20%). The Core i5-4690K was just 3fps slower than the Core i7-5960X, so it is safe to say investing in a Core i7 processor for GTA V isn't money well spent.
Unfortunately, AMD's processors had a fairly rough time in this title. The AMD FX-8370E delivered virtually the same miserable performance as the old Phenom II X6 1100T. This is a real shame as GTA V is one of the few games we have tested recently that does a good job utilizing more than four threads.
Still, the higher-end FX models such as the FX-8350 and FX-9590 delivered reasonable performance despite being slower than the Core i3.
It's worth keeping in mind that we aren't testing using unrealistically low quality settings either. The GPU tests were conducted at 2560x1600 using the very high texture settings and FXAA, so the fact that we are seeing such a variation in processor performance is made all the more shocking.
The Core i7-4770K maxes out the GTX Titan X at its default clock frequency of 3.5GHz. Increasing that to 4.5GHz netted just a single extra frame while reducing the frequency by almost 30% from 3.5GHz to 2.5GHz saw a minor 11% reduction in frame rate.
Clocked at 4.5GHz the FX series is slower than a Core i7 clocked at just 2.5GHz in GTA V which is obviously disappointing. From 2.5GHz up to 4.5GHz we see a steady increase in performance so the more frequency you can squeeze out of the AMD processors the better.