As some of you know, I'm creating a world. I would search for this, though I'm not quite sure what search terms to use.

I'm also posting this here since this isn't quite a CAW issue or a question about how to do something in CAW. Nor is it a technical problem with the game, so there's nothing to troubleshoot.

So my question is, how does the number of NPC Sims affect performance? Is the impact significant?

As of this writing, my world has 136 lots; 51 community and 85 residential. So theoretically, 680 + Service Household is the maximum population, assuming 8 on each lot. However, in practice the total is likely to be much lower than that. With an average of three Sims per lot, that would be 255 + Service Household, which I believe is larger than any EA world. Not sure about the various custom worlds out there, since I honestly haven't played any except my own.

I also have plans to add at least 15 residential lots, bringing the total to at least 100. I will also likely add some community lots, both to accommodate additional lot types and allow for additional player flexibility.

Will this world likely have performance problems on lower-end PCs? I hope I haven't overdone it with residential lots. I don't plan to build on probably 5-10% of these lots, to allow room for players to build their own lots or place some.

I think that sounds like a very reasonable number of lots, SP will balance things out so that the world doesn't become overpopulated. I think that having 3 sims in every lot is pretty unlikely and if 5-10% of lots are empty then I wouldn't worry.

There's only one of every rabbit hole, and I don't have plans for multiples of any of them. Of the other community lot types, I only have, and plan to have one of each type (except Base Camp and probably Market). The only exceptions are park-oriented lot types (Big Parks, Small Parks, Fishing Spots, and Beaches) which have multiples, and Pool, where I plan to have two of them.

I do have elevators on every single community lot that's more than one story high, but I provide a path to the different floors with stairs as well. So there isn't a single area that's not accessible without elevators. I'm not using any of the LN shells, since they aren't appropriate for this town. Some of the houses may have elevators, but most won't. I'm not sure how this would impact things.

Do ghosts count? Because that's going to put a crimp in my ghost town plans...

As far as I know, they count.

Which method are you choosing, through save game you can have ghost and they have the same effect as Sims. If your in CAW, you can't have ghosts as they will be heavily corrupted.

What do you mean? Method for what? I'm not quite sure I understand.

While I am creating a world, I've yet to create any Sims for it. I may not even create any Sims, and leave it up to the player.

However, if I was going to include Sims, my idea would be to bundle an optional save game that players can load, so they could have pre-populated Sims if they want.

I wasn't going to include them within the actual world file. Even if I knew how, I would still like to give the option for a completely empty world. I don't see any reason why not, since it probably wouldn't require much additional effort on my part.