When I started having game crashes I noticed a pattern in task manager. I believe that Windows has a 2 GB memory limit per process, so as the program reaches this limit, memory requests are being denied even if you have sufficient physical/virtual memory. I personally have 2 GB physical RAM and a 4 GB page file, but that's not the problem.

Under normal operating conditions, the program will rarely encounter this limitation (thus, why it occurs consistently for some people and not others). Playing larger maps with many planets and AIs increases the chance of this type of error. I think there were some possible bugs or memory leaks in the beta versions that were resolved, but the program still tends to increase memory usage over time; this explains the "I've been playing for two hours and then the game crashes" type of problem.

The tendency for GalCiv 2 to cache an enormous amount of data (3D textures or otherwise) is the root cause of this problem I think. The height maps alone have contributed as much as 400MB extra (~30% of total program memory usage on initial map load) on the 100% setting vs. 10% setting. The problem seems to have occured mainly with DA because of some features of the new engine or increased complexity in graphics/textures.

Although the program is prioritized for speed, much of what is loaded is not used regularly. I find about 50-60% of the memory being swapped back in during normal play. One solution is to unload certain data used seldomly (or only load it as needed). Another solution is to simply set the options so that less memory is used (this would be a user solution however; dynamically adjusting to stay under the 2GB limit is smarter). The memory used for saved games of large maps routinely starts at over 1 GB, easily reaches 1.5 GB, and eventually hits the 2 GB limit (and crashes). If this is the true cause of these recent problems, then it should be managable to fix.