Variations of Line of sight

Anyone got some good examples of pathfinding behaviour combined with the line of sight behaviour?

Whatever I build is heavy on the performance as soon as I use the line of sight behaviour.

There are some tutorials, but they use their own line of sight, Im specifically looking at the combination line of sight with pathfinding.

I have a large isometric game Im working on, and applied the pathfinding since last update, works great after the performance update.

But I cant get anything decent running when combining with line of sight. (performance wise)

So, I was wondering, who dabbled in the combination line of sight and pathfinding from the build in behaviours ?

Caps, examples, links ....

edit: I use it for enemies that walk around on a path, see the player and follow till out of sight.

How often are you using the pathfinding ? I am guessing you are not running it just after the line of sight but on some kind of timer ?

In a lot of variations ...

The pathfinding is not the issue ...

since I changed to pathfinding, I have, next to the ai dev, at least 10 extra objects doing constant pathfinding towards me, and it works without a hitch. these objects work without line of sight.

next to this, max 5 objects, doing pathfinding, while moving with a cone of 45, and stand still a cone of 360, distance 800.

Made some progress today:

I added a boolean check prior the los check, so its not using the los behaviour constantly, that made a small difference, then I changed the actions to a function, and it was even beter.

Still not as it should, though.