The problem is that survivors who did spawn are getting stuck on basic tasks, such as opening barricaded doors (which won't ever complete, since the door is barricaded, they're stuck on that task) I found one of my own npc's trying to open a door which was locked, and it kept doing exactly that. I opened the door for him and he moved on.

Now the problem is: There are probably survivors around the map who spawned and are getting stuck on those basic tasks, which they keep repeating and takes up processing power.|

I fixed this by doing the following:

make sure alt spawning and spawning for NPC's is set to low. Alt spawning can be turned off.
Basic tasks for survivors should be off as well. Then quit the game.

Make a backup of your save file.
Remove the mod in the original save file.
Load the save game, (all survivors should be removed by now)
Quit to main menu again.
Re-add the superb survivors mod.
Check the superb survivors settings. If any settings did change, set them back to alt off, basic tasks off, spawning low. Save and restart the game. Load up your save and play again.
Play again.

Hope this works..

Edit:

I kept getting lag at my own base, even after unloading and loading in the mod. Thanks to Skyver I've found out why. I had an NPC farmer. I killed every NPC I had and the NPC farmer had around 1800 seeds on him. Which if in a static container, is no problem, but when it goes into a dynamic container, your own character or an NPC for example, it lags the hell out of the game.

you have farmer? let him stop and clear the inv
youll see

Originally posted by Skyver:

you have farmer? let him stop and clear the inv
youll see

This was the problem indeed. Even after reloading the mod and resetting the NPC's I kept getting lag, DON'T use NPC's for farming, as they'll spawn in 1800 seeds which lag out the game lol