I tested this a while back and figured it had to do with either the AI pathing or the normal pathing. In either case, larger grav well sizes definitely lead to major performance hits.

I was brainstorming ways to make planets to scale with ships...1)Attach a particle effect to the planets, make the main planet mesh invisible, and have the particle effect attach an enormous planet in the background. The problem with this is that it could play the effect over top of another grav well. 2)change solar systems into planetary systems. Change the skybox to include a to scale planet. I like the solar systems how they are though, I guess you could change maps to still have solar systems...but they wouldn't be the same.

3)Increase grav well size to enormous, to scale sizes....the problem is above.

Speaking of that, we forgot to increase culture speed to match, so culture spreads ridiculously slowly making it near-useless.

Trouble with that is, everything is so small ... I wanted it to be larger. Welcome to tiny rebellion ha ha! Can you imagine how tiny fighters would be 50% of their original size