I thought I would add my input to this thread, for what it's worth.
It has also been my observation, just as others in this thread have mentioned, that after roughly two years in my forts, I see a pretty big drop in my FPS. Into the 40's. As others have stated, in the 34.x versions I could run a fort 40 or 50 years and still be at around 60ish, if I was being careful to keep things clean.
As the poster above me said, I was excited to try this current update, and loaded up an old save from I think 40.10, and ran it for a while. Unfortunately I didn't see a pick up in my FPS at all
.
I heard someone suggest at one point in another thread that they thought perhaps the new trees have something to do with it, but I have no idea.
I myself am wondering at one particular behavior I noticed in my 40.x forts. Mind you, I last played 40.10 I think, and haven't had a chance to play really since then. But in those versions, I noticed that if I retired a fort after say, 3 years or so, and then made an adventurer and started that adventurer off in the fort I just retired, that the map would absolutely fill up with former merchant caravans that had visited my former fort.
Those were definitely the old caravans that had been there, because I at one point took note of the names of a couple of traders, and saw them on the site as an adventurer. I don't think that's enough to account for the FPS issues of course, but it seems like some stagnant data about previous traders and their caravans may be staying with the fort; data that may not have to be kept, or maybe wasn't even intended to be kept as such. Again, who knows if that's significant in any way, but its something to keep in mind I guess.
At any rate, I'm hopeful that things will improve as Toady has time to work on stuff
.