Look & tools

Keeping a big fortress running smoothly

A young fortress races along. An old one can crawl. That is the cost of simulating everything, and there are sensible ways to keep it in check.

Sooner or later, a successful fortress starts to feel sluggish. Seasons take longer to pass, dwarves seem to move through treacle, and a simple task like hauling stone becomes an afternoon's wait. This is normal. The game is doing an enormous amount of work every moment, and a big fortress simply gives it more to do. Understanding where that work goes makes it much easier to decide what to change.

Why the game slows down

The principle is simple. The official wiki's page on maximizing framerate puts it plainly: every extra thing the game must track costs speed, and reducing how much is active keeps it quicker. The same page reports that most processing time in larger fortresses, over 60%, goes on units taking their turns, and that only a small part of that is pathfinding. In other words, the biggest costs are the creatures themselves and everything they are thinking about and reacting to.

That breaks down into a few main sources of load:

• Creatures. Every dwarf, visitor, pet, livestock animal and wild creature takes its turn: deciding what to do, where to go and how it feels about it. More creatures means more turns.
• Items. Every stone, sock, bolt and barrel is an individual object. Items mostly sit still, but they still exist, and the game still checks them for things like temperature.
• Fluids. Moving water and magma are calculated tile by tile. A still lake costs little; a churning river or a pump stack running constantly costs much more.
• The wider world. The world beyond your fortress keeps living its history, and a very large world with many civilisations has more going on in the background.

Habits that help

None of these need extreme measures. A handful of habits, adopted early, keep most fortresses comfortable for a long time.

Keep loose items under control

Mining produces enormous amounts of rough stone, and much of it is never used. Fortress-wide clutter adds up. Players commonly reduce this in a few ways: turning surplus stone into blocks or furniture that consolidates many pieces into fewer objects, getting rid of worn-out clothing and refuse, and not letting workshops churn out goods nobody needs. The official page explains that items mainly cost speed because each one is checked for temperature, so a fort holding fewer of them has less to check.

Keep water and magma calm

Fluids are cheapest when they are still. Contain rivers rather than letting them flood caverns, switch pumps off when they are not needed, and avoid designs where water constantly cycles for no reason. The water and magma pages cover how to set up both safely, which tends to mean efficiently as well.

Mind the animals

Livestock breed. Cats breed with particular enthusiasm, as the animals page explains. A fortress that starts with a few pets can end up with dozens of animals all taking turns. Keeping breeding in check, and not letting herds grow far beyond what you use, helps both the framerate and the food supply. The official page also mentions that caged tame animals are exempt from many of the checks that free ones require.

Design for short trips

Although pathfinding is a smaller share of the cost than people assume, sensible layout still helps. Wide central corridors, workshops near their stockpiles and a compact core mean fewer long journeys and less searching. The rooms and layout page covers this from the point of view of happy, productive dwarves, and it happens to be good for performance too.

Choose a sensible population

More dwarves means more of everything: more turns, more items, more animals, more hauling. Many experienced players cap their population at a level they can manage comfortably and find the fortress more pleasant to play as a result. There is no correct number, and the right cap depends on your computer and your patience.

Think about it at the start

Some of the load is decided before your first dwarf arrives. The same official page notes that smaller worlds with fewer civilisations and beasts leave less happening in the background, while still being interesting to play. If performance matters to you, a modest world is a reasonable choice. The world generation page explains what those choices affect.

What not to do

You will find advice online to switch off whole game systems for the sake of speed. Some of it works and some of it breaks things in subtle ways; turning off a simulation the game relies on can cause strange behaviour much later. For anything beyond the general habits above, read the official wiki's current guidance for your version and change one thing at a time, keeping a backup of your save before you start.

Accepting a little slowness

Finally, it is worth remembering that some slowdown in a large, old fortress is simply what success looks like. The detail that makes it crawl is the same detail that produced every story you care about. Tidy what you can, keep the rivers calm, and enjoy the view. The community tools covered on the utilities page include helpers for some of this housekeeping.