At a high level, pathfinding 1) provides tools and functions to enable smoother and smarter movement behavior for non-avatar entities in Second Life (for example, monsters in a game, rats in a haunted house, wisps in a fantasy forest). We refer to these entities as characters; in gaming terminology, they are sometimes called NPCs (non-player characters) or mobs (mobile objects).
Up till now, content creators had to use resource-intensive scripting workarounds to emulate intelligent character movement. With the addition of pathfinding, content creators will have a much easier and better performing way of creating characters that can move around in the world. Characters can use LSL functions to avoid obstacles, move around corners, climb inclines, and move across region boundaries: things that are very difficult or even impossible before. Pathfinding will also enable new gameplay mechanics, such as creating food that attracts monsters.
Note: Pathfinding is not an animation system. It does not provide a way to animate a biped or quadruped in conjunction with the new movement functionality. You must use existing methods to animate characters. Nevertheless, pathfinding enables more dynamic movement and provides a better system for controlling character movement than was previously possible.
See here for an excellent overview by Inara Pay.
For more information, consult the SL wiki. Specifically:
Here is an excellent page on ways in which you can optimize objects on your pracel for Pathfinding:
Currently, only Region Owners and Estate Managers can work with Pathfinding tools, and only via the Region Debug Console.
To access the Region Debug Console, go to the top menu bar, Develop → Consoles → Region Debug Console.
Press Ctrl-Alt-Q if you do not have the Develop menu enabled.
agent set allow-modify-navmesh true
agent set allow-modify-navmesh false
If you have no intention of using pathfinding in your region, and don't want to set up pathfinding, you can disable dynamic pathfinding like so, to save CPU cycles:
set dynamic_pathfinding false