Putnam asked me to upload my 400-dwarf fortress so that he could take a look at it. I'll upload my three >400 dwarf fortresses which all exist in the same world. I am using the vanilla version of Dwarf Fortress without mods.

The third fortress is called Stonemark. There are over 400 dwarves in this fortress. No cavern layers have been breached. The fortress typically runs at around 10-20 FPS. I have a large number of merchants that show up from different civilizations in the summer and fall. I also have a large military over >150 dwarves that I bring out at the start of the each season to face the sometimes large sieges that show up. When the military is training my framerate falls off enormously to around 10 FPS. If I only have 1-2 squads training I am closer to 20 FPS. And if I have a lot of my military off-map on missions my framerate will climb further to nearly 30FPS.