I have an i5-3570K, 8GB RAM, and R9-270X 2GB.

I just tried playing 100+ (near max) civs on excessive map size (second largest map setting) with abundant minor civs.

By turn 90, the map was no longer stable and playable, as it would crash from the following:

1) Twice crashed - when I was deleting buildings to reconstruct new stuff

2) Once when the turn ended.

I'm not sure if everyone experiences this, but I have to conclude that even with a computer way beyond the recommended setting, 100+ players on immense map size is not feasible because:

1) It crashes later on

2) Takes 45 secs per turn to load by turn 90. 

Other things to note:

1) During the start, loading time was only 10 secs at most.

2) I did set around 8 civs to "god-mode" AI, 20 or so to "genius and gifted" AI. The rest were normal. 80% of the galaxy was fully colonised by turn 90.

3) RAM usage was around 3.4 GB.