Hey, i think i found 2 issues that have a big bad effect on performance in my current game. Note that i am using version 4.0.31 .
The smallest is about having cloakers mixed in with groups that are on a planet with enemies. I don't have a save in that situation right now, but if you look at an old chokepoint in the attached save on Ifiwocen (bottom of map) where i've got my build queues aimed, i used to have to turn off my cloakers while in the pack. Note that the ships were not fighting since they were far behind the large number of turrets, they never did decloak, but just having the cloakers activated in the group really slowed things down.
The biggest issue is pretty nasty and I'm not sure exactly what causes it. If you look at the save at Tuseliu (right side of map), i have put forcefields over the entry wormhole to keep all the runners in front from escaping. I think the issue is forcefield collisions since the enemy ships sometimes become trapped between them, but maybe it's all the turrets shooting. Anyway, the save has less than 20 bombers caught there getting shot and the game takes 2-3 real seconds for each game second, and that unpleasant lag goes the moment the planet is empty again. And that's on a reasonably fast computer with 2 cores using the second worst performance profile.
