The picture below is what I was dreaming of and thinking on for years, maybe since I bumped into three.js at the first time
The demo is not perfect, but working on it gave me the understanding of principles of how things work (or I like to think, that I understand them )
Highly recommend this blog post: FBO particles – Youpi !.
Also, @akella 's video helped me a lot: FBO Particles with Three.js #10 - YouTube
The scene of 4 million points runs with 75fps on my GTX1060 (FIrefox).
If you want to make a nice screenshot, just hit “S” key to switch stats and gui on/off.
Source code: white-currying-4li5k - CodeSandbox