I will happily be corrected if I'm wrong but as I understand it, the looooong turn times in CiV were largely due to the 32-bit format. (For those who don't know, this puts a hard cap on your RAM usage at 2 GB - meaning even if you have more ram available, the program won't use it). Since this is a 64-bit program, that alone should reduce turn times significantly.
Edit: Ed Beach just called. He said turn times should be 1ms, maybe 2. He also said a civfanatic should be our next pres-o-dent.
32bit has nothing to do with AI processing.
The bit size is like the size of a plate. If you eat a lot, it helps so you don't need two plates, but if your portion is small enough that 32 bit plate is enough, it makes no difference.
The reason AI takes a long time is because it has to do everything sequentially. How do you contemplate a good place to settle if you don't know the surroundings? That alone is already sequantial. Then the combat, then building order, and so on and so forth