I am becoming suspicious that the crashes I am seeing may be related to the size galaxy I am playing. It may also have something to do with the amount of resources available (but I don't think so in my case) so I am including some hardware information. If everyone could post an answer to this questionnaire, perhaps we will find a pattern.
OS RAM GPU GPU RAM Galaxy size Crashes? # colonies # civs Turns Notes
Win8.1 16G GeForce GT 640 4G Large Yes. 15 4 25+ Crashed during EOT.
Win8.1 16G GeForce GT 640 4G Medium Yes 28+ 4 50+ Crashed assigning Starport Sponsors.
Win8.1 16G GeForce GT 640 4G Small 1 27 4 150+ Crashed once, restarted OK.