I'm pretty sure I have read that one of stardock's goals with 64bit multi-core support is that the AI will be working on its turn, while the much slower human is performing his/her turn.  I've got a soak running on insance galaxy, 16 races, max minor races, and I dont see as much impact as I would have thought.  

I'm at turn 463, the planets are certainly all settled, with the possible exception of harsh terrain planets.  Initially running the game, it would take 8-9 seconds during a turn while running my turn. Now at 463, it takes about 32 seconds.  That baseline is from taking my take, a few minutes, and making sure my cpu-util has dropped as low as it can go, ensuring the AI has done all the work it could "during" my turn.  

However, when I go back to soak, its taking about 40s to complete a turn.  I am assuming the human player only requires one thread and all other races require 1 as well.  Therefore when I am in control, that 32s is spent solely on calculating things like influence changes, new planetary stats, etc. - i.e.  The "interaction" part of the turn, and the final results part of the turn.  Its taking only 8s for the 16 majors and 10 minors to perform their turn.   That 32s seems like quite a large % of the overall time.  

I'm wondering if stardock has consider for the engine to actually carry out ai vs ai interactions first, and all interaction in between turn computation, while the player is continuing to perform the turn, however being prepared to roll the results back based on the human's final decisions.  The rollback could even be done during the human's turn, in between various interactions.  This would take additional memory, but once you go over that virtual memory barrier, its pretty much downhill anyways.  Accessing virtual memory will always be slower than physical memory, but fortunately not as bad since the development of SSDs.  However in this time vs space complexity problem, time is still the loser, all the time, whenever a human is involved.  

Performing the common inbetween turn tasks (that 32s per turn for me as of now) could then be virtually eliminated, when a slow human is involved and near always takes atleast 32s to perform a turn during midgame and later. 

I bring this up, as the needed AI algorithms to better balance the game, and future complex feature content, will slow the in between turn time much much more. AI algorithms however fall into the non-interaction category and would be performed during your turn - nevertheless, just wanting the game to be faster in between turns - I've seen lots of post by the people playing insane size, that mid-late game, the time in between turns becomes unbearable.