To breathe some life into Tamriel's empty cities, I created a mod that adds approx 200 unique NPC's to cities and towns. To give them personality and "jobs," all are unique with their own unique sleep, eat and wander packages. As it is, the mod works as intended; however, I notice others have approached this differently in mods like Crowded Cities and the like, using leveled spawns to produce NPC's in cells. In terms of CPU usage, I am curious as to which method is more efficient? What do you think?

If you want them to have jobs, sleep and eat routines you can't use leveled lists. If you do, they can never leave the cell they're in unless you're there with them. You'll just end up with NPCs that get stuck doing the same behaviours over and over again.

Yeah, I like the added realism of unique NPCs, but I am concerned the 250 extra AI packages running in the background taxes scarce resources beyond what it returns in added immersion. I am under the impression the game is forced to keep track of all these added NPC's while I am away and hurts performance when it counts. My game is pretty much at its max in terms of CPU usage, so I am trying to gauge the relative cost of features I want to keep and am fuzzy about the game mechanics here. As it is, disabling one or the other doesn't seem to make much difference in my new game, but in the past I have had NPC's freeze up on me as the game advances and am trying to avoid that in my new game.

The real performance hit is not from the game tracking them when you are not around, but when you are right in the midst of them. What are your system specs? Many users sacrifice 10+ FPS to use mods such as BC, and there is not much to do about it either. I think the approach would depend on what you were looking for, but I think 200 unique, always there, NPCs is more immersive. It depends on what they are doing, I guess. The hit would occur wherever the most crowding at activity is. You could always try a "stripped down" version, and add until you think the cost is too great. It should not be hard to see the trade-offs.

Thanks TomLong.

I have a mid-range system:

Phenom II 710 X3 @ 2.6 ghz
4 gig RAM
ATI 5770 1 gig VRAM
Win XP Pro

If I understand you correctly, as long as I am not in the same cell, the game isn't burdened significantly by the NPCs outside of that cell. If that's the case, then I will stick with unique NPC's because I hate empty cities.

Low level processing of NPC AI is nothing to sneeze at. Though it may not be much, each NPC the game does need to track adds to the performance load. The less of them you have to deal with, the better.

Any NPCs you add for realism that you can get away with using "no low level processing" on, you should. Tomlong already listed drawbacks to that, but unless it's critical to have all 250 of your NPCs doing complex schedules, those drawbacks are minimal and the gain CAN be noticeable even on high end systems.

Link to said mod please?