I reset my Mac and the problem was gone. Maybe it was something slowing down the game.

Loewchen wrote:Nothing wrong here, you have vsync activated, so once you fall below 60FPS your drop to 30. Deactivate vsync if you do not like the behaviour.

I've always had Vsync activated and this problem wasn't present before, so I don't think that's the source of the issue.

Rolled back to version 14.23 and the problem still persists so it might be a OS related issue.

So after updating from macOS Sierra to High Sierra, I've encountered this weird issue. It's happening on previous saves and new games.

Whenever I'm in the middle of nowhere or near minerals, FPS and UPS are 60. Even with some trees it still can run at full speed. But going near forests and inside ...