I'm running DF 34.11 and my past few forts have around year two or three started lagging with different numbers for population, as well as layouts. I've changed settings (Disabled weather, temperature, invasions) and had no luck, I've had this problem since 34.10 and gained no understanding of the cause. Originally I assumed it was my crappy laptop getting worse... (I'm running vista 32 bit, 2 gigs of RAM, a 1.6 GHz Dual core processor) I've tried eliminating unnecessary paths around the fort, reassigning traffic designations, setting the high designation to match normal, even a suggestion to remove wells with no luck. No hidden fun stuff, no (visible) invasions, nothing.
It lasts about 30 seconds then I get about twenty of game play, there's no apparent change in CPU usage before, during, or after these periods of lag. This lag only happens while the game is running, if paused it's perfectly fine. Attempting to preform actions (click, pause the game, activate the "look" mode, etc) will cause nothing to happen at first, but once the lag is over the game will execute them though I've noticed if you try to do more than a few things windows will determine dwarf fortress is "not responding" and ask me if I want to close it.
The only "consistent" variables I can think of are one: I have a tenancy to stockpile (at least what I believe to be) obscene amounts of metal bars (At one point over 10 thousand) and I'm also using Dwarf Therapist and DFHack.
If anyone has had experience with this, or at least some more suggestions to possibly fix this I would be greatly appreciative. Also, Apologies in advance if this is on the wrong thread wasn't too sure if it was a bug or me just being stupid. I would very much like to get back to loosing forts to fun as apposed to lag.