I created an account just to post this.
It's definitely not the Nvidia drivers causing the problem. I'm still on old drivers from 2017 (version 388.13, to be exact), as I've had no reason to update them. I've noticed a HUGE dip in performance in 2.2 compared to the last time I played.
I never played 2.1, but in 2.0 the default medium galaxy ran just fine all the way up to the year 2500 and beyond. Certain actions in late game would make it stutter a little, but it was easily playable as long as I wasn't on a 1000 system size galactic monstrosity. Now, in 2.2, I tried to play a game with the default medium settings, but the stutter got so bad that it was literally unplayable after the year 2450 or so. It's so bad that the game progresses at 1 month every 40-50 seconds, and most clicks don't even register.
I can't pinpoint exactly when it got bad, but I noticed it was around the time the unbidden showed up and got into the L-gates. This is my first time playing with the L-gates, so I'm not sure how they work. However, I've done a bit of research and it seems stutter after opening the L-gates was a common problem in 2.1--so I believe this issue may be related. I could imagine that the Unbidden AI were behaving stupidly with the pathfinding of their fleets, or something similar. I would have tried to drive them out to see if that could help, but the stutter was so bad that I couldn't tolerate continuing to play.
There are a couple things I've observed:
- This stutter happens exactly once every game-day, at the start of the day. Once I see the counter increase the date, everything on the screen will appear to pause for half a second, or perhaps longer. Then, once this has passed, the game continues as expected with smooth frames and mouse movement until the next day.
- Another thing I noticed is that the UI animations do not pause when the game is stuttering. For example, there is an outline on the "resource storage full" icon that moves from the bottom left corner to the top right corner. When the game resumes from its stutter, this outline "jumps" some distance away from where it was at the start of the stutter. This makes me think some other thread is still able to work its way through the animation during the stutter, even though the display isn't getting updated.
From this, it appears that there is some new change in 2.2 that introduces a huge load on the CPU at the start of every day. Further, I speculate this occurs in the game itself, and not in any of the UI or graphics elements.