Prefabs (linked/instanced 3D models) in Blender often lag because the base prefab’s high polygon count, active complex modifiers, or unoptimized rigs/animations increase viewport processing load.
- Blender’s viewport processes each prefab instance in real-time—so a heavy base model (e.g., unapplied subdivision, dense meshes) multiplies the work. - Rigs with many bones or shape keys, or missing viewport optimizations (like disabling modifiers in "Viewport Display"), also slow things down.
If lag persists, try simplifying the base prefab (apply unused modifiers, reduce polygons with the Decimate tool) or use Blender’s "Simplify" settings (Viewport → Simplify) to lower subdivision levels temporarily.