In two recent campaigns with Precursors, Star Swarm and Invaders switched on using Aurora 5.14 and 5.42 I managed to reach year 68 and 66 years respectively of the game, before the turn delays became intolerable, the record being one day of gaming taking six weeks of real time. When the designer password was available it showed most of the delays were due to the Invaders interacting with Precursors or Star Swarm. However towards the end it was difficult to positively identify what was causing the delays. Only two or three times in the 5.42 game was the slow down due to Invader interaction with NPR races, which was invariably fatal for the NPR.
Thus my experience is that if you switch on Invaders you probably only have 66-70 years of game time to play with. The reason appeared to be connected to the rate of Invader exploration. With the designer password it was possible to see they had explored hundreds of systems compared to much less for all other races. In the 5.42 game Invaders had explored 1118 systems (in a thousand star game!), seven of the NPRS had explored 100, 16, 6, 4, 88, 26 and 12 systems respectively, the player race had only explored 23 (I turtled). Precursors had knowledge of 184 and Star Swarm 75. That game lasted 66 years.
In the 5.14 game I don’t have the data for Invaders as trying to eliminate an Invader fleet in designer mode I crashed the game and eliminated such data for Invaders but the player race had explored 42 systems, five of the NPRs had explored 67, 78, 133, 174, and 2 respectively, While the Precursors had knowledge of 44 and the Star Swarm 32 systems. I would expect the Invaders to have had explored around the 1000 system mark going on the event record for them.
I guess you could limit the number of stars to a couple of hundred, but that means with the rate of Invader exploration they are going to find you pretty quickly. Another way would be to greatly slow down Invader exploration of the galaxy or if the Invaders discover a system containing either Precursors or Star Swarm to nullify that turn of exploration.
My choice would be to make Invader incursions a quite rare event so they would only intrude into a new system in the Galaxy once every 1 to 5 years, perhaps make it possible to specify this interval at the game start? I would not have them explore unless they find enemy ships or colonies when it would be reasonable for them to attempt the extermination of the foe.
I have started a new game with 5.56 without Invaders and 58 years, 80 systems explored I have had no slow downs what so ever – so far, although I may have eliminated the primary NPR early on!
Anyone have other thoughts