To what extent does System Size use up the memory of the PC?

Weird question, probably, and not phrased very well because I’m quite a n00b when it comes to how a computer does its job.

Suppose you’d scale, say, California to 0.1 on the NavMap, and put up a very huge planet on the edges of the System (as it seen on the NavMap), quite far from where all the action is happening, how much more work would your PC have to do?

Would it need to reserve memory space between the center and the remote planet?

Would it matter (I’d guess: yes) if there would be a traffic pop zone and a station near the remote planet?

Would it matter if the remote planet were a non_targettable?