@jlampel I definitely need a new computer 😉
But on my machine, 1000000 hair particles perform the same as 100 particles with 10000 interpolated children; more Viewport lagging that in your GIF.
It gives about the same performance when using GN with visually the same Instances density. But when using Dynamic Paint, like I did, for the Camera Culling, Hair Particles update a lot slower than GN.
strategically placed, in the foreground only
I will try, but foreground is not really defined, as the Camera will be moving around…