My solution was smashing my old laptop that had 6 gigs of ram. Well i didn't really "smash" it. The laptops demise was coming, and i had plenty of warning. I had to get a replacement until i can build a new gaming rig.
Now i use a laptop with 8 gigs of ram that has a free upgrade slot, and it will get that extra ram soon.
On the old laptop Gal Civ 3 would hard freeze. Even on tiny maps with only 1 opponent. I would task manager the game, and was shocked when i saw it was using 4.6 gigs of ram right at game start. Consider this for laptop users. You may have 6 gigs of ram, but your GPU will use a chunk of that ram strictly to render. My old laptop set aside 1.5 gigs of ram strictly for the GPU. So in reality i only had 4.5 gigs of system ram available. Which Windows 7, and other programs like steam used up about a gig of that ram. So it was no wonder the game locked up when it went over 5 gigs.
My new laptop has 8 gigs (which thank god its upgradeable), but it sets aside 1.7 gigs for the GPU. That leaves me 6.3 gigs for system use. Which about a gig is used up by Windows 8.1, and other programs. Gal Civ 3 no longer hard freezes, and i can play a decent game now, but i don't dare try to use larger maps, or more than 2 opponents until i can get some more ram.
The point is be careful. Laptop users don't have as much ram available as you would think. Your GPU will take up a good chunk of that ram depending on your GPU, and manufacturer.
