P Storm + Turbulence + Self Collision Event + Gravity + Wind
3 separate emitters are involved, 1 is emitting 2nd is falling down and generating particles on collision 3rd is a random one. No Geometry involved.
Simulation took 5 Hours on Xeon E5-2620 64GB Ram and Dual GTX 690 Setup
Render time was 9 Hours on same system

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