If you are getting lag in the system map screen mainly where you may have lots of ships, go to the display 2 panel and shut off max combat weapon range(ships) and max fire control range,
They are nice to see during combat but apparently zooming in and out with lots of combat capable ships in system = MAJOR LAG.
it was using an entire single core on my quad core and lagging really bad with my fleet sitting on earth and I was really getting irritated till i started turning on/off everything and found this fix.
So in short-
Fix for system map f3 screen lag for moving camera view around/ in and out.
unclick fire control range and weapon range boxes in the display tab.
