A quick performance update.
I am about 12 years into my current campaign. There are two NPRs, plus some active precursors.
There are 154 systems with a total of 13,000 system bodies. Orbital movement is on, including asteroids.
There are 788 ships in 337 fleets, including 156 civilian fleets. 262 of those fleets are under AI control.
There are 70 populations.
C# Aurora does everything that VB6 does, plus all the new functionality.
A 1-day increment is taking 1.3 seconds.
A 5-day construction turn is taking 1.7 seconds
This is on a PC that was good three years ago
I am also running in debug mode, which is probably a little slower than normal.