Thanks for the reply.

What happens that makes you want a better card?  Is it slow or unplayable, or do you just have to turn the quality down lower than you would like?

The graphics in GalCiv3 don't seem to be all that demanding to me. They're not exactly high def.  I'd think getting more memory would be the key to a faster game here.

I started out with 8GB and I also play on a laptop that has 4GB and integrated graphics.  The laptop is very slow, but handles the game. 

I upgraded my desktop in steps from 8 to 16 and finally 32GB.  I saw a vast increase in perfomance with 16GB, including no more crashes to desktop or game freezing.  32GB made no noticeable difference.

The desktop has a fairly low end card (GTX 750, 2GB) and handles it well.