Sometimes, Aurora just has a lot to calculate. Aliens shooting at eachother and whatnot.
However, I have a fix for improving average process speed.
Upon starting the game, I open the Vista Task Manager (accessed via ctrl+alt+delete), click the processes tab, locate the Aurora 32 process, and set its priority to High (or Realtime).
I observe noticeably faster 5 day intervals after doing so (running a core i7 processor)