I have 550 logistics robots hanging around and about 1000 construction robots, but those are stopped unless I'm building stuff. There's also the 7 trains moving around. The factory is not too big, from what I've seen in the wild. You can see pretty pictures of it.
Here's a screenshot with the debug info on, showing the paltry 30 FPS I'm getting in my save:
![Image](https://dl.dropboxusercontent.com/u/34534935/factorio/fps/fps-small.png)
On a new game and also for quite a while in my save, the game runs fixed at 60 FPS. The FPS drops were noticeable, like "The game is running slower, what's up debug screen? Dang, it's only running at 50 FPS!". Repeated for 40 and now 30 FPS.
If someone could see if indeed I'm breaking the game, the game is broken or if I should throw my computer out the window, I would be so pleased.
More technical info below.
Screenshot of new game with debug info:
![Image](https://dl.dropboxusercontent.com/u/34534935/factorio/fps/fps-new-small.png)
Linux x64
Intel i5 650 3.2GHz
Nvidia GT 220 1GB
12 GB RAM