Would world actors work properly if they were too far away?

I’m developing an open world game.
NPCs spawn in many parts of the world.
And they are not within my sight.
So the game doesn’t load them as models.
But all npc have a task and they have to do it constantly.
Do you think the game calculates NPCs movement, work and event,
even if they are model not loaded?
If not calculates, I’ll have to think of another idea for npc’s.