Basically, on low, medium, and high game settings, how many npcs can you have on the screen before you get noticeable lag? As a location reference, pretend you are in Solitude.

It really depends on the computer's hardware. On mine, I notice no FPS loss with 15 additional NPCs walking around in Solitude unless I have them all crowded in an area and I'm looking down from a high area.

3.0Ghz hexcore, 8 GB RAM and a GTX 560, Ultra at 1080P. My average framerate outside is 35, when I spawn in 20 or more NPC's using the console I don't notice much of a loss, if any.

Thanks! Needed to know this in order to determine what would be the ideal amount of npcs walking around in my city. It's a little hard to tell with base game towns, for different rigs.

use fraps, then go to the highest point on your city, or use tcl and fly up into the air (not too high), just enough so that all your npcs and a good chunk of the city's architecture are in view.

then compare your FPS to that of Markarth at the top of the hill right outside Understone Keep


if your FPS is lower than Markarth, you are ok.

I'm using 2500k OC'd and GTX580 OC'd so it's hard for me to "eyeball" what will work for various rigs
i use Markarth as a base reference for everything i build because that is the only area in skyrim that consistently drops my FPS below 60 (its a good stress test reference point)

For some reason I thought Solitude would strain computers more. Will have to look into Markarth. Thanks.