Just goto Options under "Advanced settings" and remove--> "display nebulae clouds in systems" Just decrease your FPS to 15 or anything lower then 50.tbh or just remove--> "unlimited" FPS... put star Density all the way down, and increase your system cache to 12mb if you have the space.
This has worked Amazingly for me 100% better when you have the largest MAPs 16x16 with 1400+Stars. give it a go.. it will make your game faster. did for me.
Youll notice the improvement of speed mostly in the bigger maps only.