
Originally Posted by
fdski
Unlimited memory allocation OFF.
With 16GB of RAM you should definitely let that ON everytime! It may solve your problem, because your CPU/GPU seems to be decent.
I have a worst computer and except in extreme cases (as Leving said, mostly when there is tons of units involved, and if its a settlement battle, or both) I dont have freezes. Its not very fluid either, but thats my problem: I prefer quality for screenshots and good aerial view 
What also worked for me, was putting "shadows" and "unit details" always a notch below the other settings, and never at extreme.
Also do not activate vegetation alpha.
Here's my personal settings, I advise you to try and see if it works with your personal unit size.