What's your systems specs?
I don't have all of the specs with me here at work, but here's what I remember on that PC...
It's an ASUS Socket 775 AGP MB. I don't remember the exact model, but it was a pretty high end one for its day.
Intel Dual Core 940 at 3.2 GHZ with a Scythe Ninja Cooler.
ATI X1950 Pro AGP Video.
4 GB of matched RAM.
Western Digital 120GB SATA x 2 and 120GB EIDE x 1 HDs.
CoolMax 600W Power Supply.
WinXP Pro SP2.
I'm using a memory manager that I only need when I'm playing GalCiv2. I tried the game without it and it would crash continuously, early in the game. That even happened sometimes in DL though.
It slows down and freezes a little during every turn now (middle of year 3). The freezes happen throughout the turn, but also every time a ship is destroyed. The battle screen freezes a lot.
The crashes occur randomly, but it would also crash every time I tried to upgrade a particular morale mining starbase with a constructor. I destroyed the mine and rebuilt it and those crashes stopped. It had a fleet rally point on top of it, if that makes a difference. The rally point is still there now without any problems.
It was crashing during the quick saves for a while and when it did that, it would erase the previous quick save. Luckily, I have the game saving every turn, so I only had to replay the last turn each time that happened.
It also crashed and erased the autosave once, but I had a good quick save for that one. I've been relatively lucky on that.
Needless to say, the frustration level rises on every crash. Maybe I need a slower/older computer with less memory?