... I typically use a 4x3 or 3x4 embark area. As for worldgen, I limit to 2 cavern layers, and basically make the caverns and the spaces between them to be 5 z-levels. What sort of exacting specifications do you recommend for getting good FPS?
I should mention, my system specs are very modest by current standards. I have a core2duo 3ghz with 4GB of DDR1066 RAM.
I'm going to provide some caveats before I provide this information, because I have some very strong bias.
My personal style of play is sort of a lazy/efficient combination with a strong dose of rationalization thrown in. As such, I tend to work backwards from my goal and see how I can refine it. What is fun for me is very likely not going to be fun for you, or possibly not anyone else. Just keep that in mind.
In my case, once I discovered goblin sieges, I wanted very much to see the limits of how large a siege I could withstand. I've used moats, water systems, magma systems, military, no military, cheats, no cheats, evil biomes, good biomes, savage, not savage, surface, and underground forts.
To that end, I started out with a pocket region, and the default raws, and tried to get as many goblin civs as possible. Turns out, about 5 is the limit. They won't build dark fortresses too close to each other. But then I also found that with the default raws, you only get one goblin civ interacting with your fort. Even if you have 31 distinct goblin civs, by default, you only will ever have one on the civ screen.
So, I changed that. Added 5 more goblin civs. Now I have 6 goblin civs to siege me, alright! progress! But, there are an awful lot of other things in the world that I really have no interest in. I typically breached the caverns and then never gave them a second thought, using the soil layers for tree farms and that was that. But all I was really using the caverns for was wood. Forgotten beasts kept showing up, and they just roamed around the caverns dusting, burning, and wandering their way to and fro. Never needed to go down there, so.. really, no point if I could get the wood elsewhere, right? So, i axed the caverns and gave dwarves above ground farming.
I tend to stick with 65x65 as a max world size now. Not everything fits into a pocket region, and some aspects of worldgen need a larger set of regions to really tweak properly. However, very flat and/or small worlds do have one advantage. Everyone can reach everyone else, so often I can get 2 goblin civs at war of the 6 i have per world, which is great, that means early sieges right away.
Now, without the caverns, there's none of those annoying animal men, just normal animals. Fewer things pathing around, fewer things to keep track of (for the game engine). Faster! I used to play entirely on deserts or badlands, but had to switch to wastelands to get some above ground trees, as there were no belowground trees now. In addition, I was using an elevation mesh to get mountains in my maps, just enough for dwarves to start on. Except, you don't really need to do that. You can make dwarves start anywhere, in any biome. One line in the raws, and they will happily live on wasteland. No more mountains.
Ok, so could I get rid of rivers? Well, in the past, I was always looking for embarks with rivers and a volcano. Rivers and a volcano. Always a river and a volcano. It was like a sickness! After generating dozens and dozens of worlds, and searching embarks for hours, and building forts on those sites, the efficiency kicked in again.
One command in dfhack provides a riversource tile and permanent water for an entire fort, regardless of biome. Done. Buh bye rivers. How about volcanos? Most of my forts have a goblin melter in them, and they need an infinite source of magma. For the moment, dfhack won't create permanent volcanos, so they're an unfortunate reality for those forts. However, on many of my forts, which are defended by trap hallways, I only need magma for my forges for convenience. Again, two commands in dfhack, and the forges are magma powered. I've done it the "right" way, so I just move past that now and do it the fast way.
I tried necromancer sieges, but the way zombies shrug off magma seems broken to me, so, no more necromancers, although their sieges are VASTLY more entertaining than goblins, as they never run away, which is awesome, especially with automated defenses. I spend no time on the surface, so removing evil clouds, evil rains, and all the rest of that seemed prudent. I removed mandates from nobles and artifacts, so now my nobles are extremely friendly, never kill anyone, and I make them truly legendary surroundings as a reward for not acting like petulant children. heheh.
Along the way, I removed elves and humans, diplomats and caravans, and creatures I really don't want to fight. My worlds have very few if any surviving dwarves, one dwarven civilization (usually dead), dozens of thousands of goblins, and some animals. That's pretty much it. I want to fight goblins, and I get to fight goblins. I set my FPS limit to 500, and I am always at it unless I breach a volcano for automated defenses. After that, the fluid flow is pretty substantial after a siege, but I'm moving 520 7/7 tiles of magma per cycle of the grand goblin melter, so really, the game is doing a damned fine job, in my opinion, fps-wise.
I also figured out how to paint elevation, volcanism, and other features with the "Preset Field Values" part of the advanced worldgen interface. That was very educational. I learned about the temperature ranges for worlds, and frostbite and fat-melting, what the consequences are for adding more civilizations, and the difference between sites and civilizations, and what will inhabit a site versus a civ starting point. Also learned how to add or remove kobolds, or increase the likelihood of massive rivers, cliffs, waterfalls, and similar features.
Recent features like the refuse stockpiles for rotting away armor, clothing, and so on has also been helpful, FPS wise, and has lessened my reliance on atomsmashing or dfhack:autodump-destroy-here. I routinely build a magma pit for dropping the dozens of kittens that show up for vermin control, and i desperately hope animal traps will be fixed soon so there will be a reason for large jewels and I can stop taking cats on my embarks. However, I pit or kill all animals except my cats, and keep it to a maximum of 3 adult cats, and 3 kittens. Once the kittens are grown, I kill the adults and wait until the next set of kittens is ready. Toady, if you read this, please make vermin gem traps work so I can stop killing kittens.
I want very happy, very rich, very safe dwarves in long term forts, and I get it all. You can tailor your worlds and the game (with very easy changes) to suit your playstyle, and it should be faster, in the end.
