In this Unreal Engine 5 Niagara tutorial, we break down the core differences between CPU and GPU particle emitters. Learn when to use GPU for millions of particles, why fixed bounding boxes matter to prevent culling, and which features (like Light Renderers, Simulation Stages, and Event Handlers) are supported on each! 
https://dev.epicgames.com/community/learning/tutorials/197BV/unreal-engine-ue5-niagara-basic-cpu-gpu-5