In my experience, the only way to make Aurora playable for many in-game years is not in fine tuning your machine, but in tuning Aurora.
Don't enable the Invaders when you start a campaign and, possibly, play with no NPR, they will be generated automatically in any case, while you explore the galaxy. If you want more races to compete, manage them yourself. Up to three it's manageable. Other things that come to my mind are keeping the galaxy size to a reasonable level, and trying to avoid fast growth of the shipping lines; don't subsidize them. Disabling asteroids orbits also helps.