I've not had to do this in the past yet, so I might be missing something easy…

So I have a scene with a particle simulation that repeats along the edges. It has 9 million points. I'm creating about 3000 packed copies of it in a tiling pattern. When the points are just points (spheres) I can render it quickly and with low memory.

So now I want to replace each point with a packed disk prim, with a total variety of about 100 packed disk items. And when I do that, I wait hours before even seeing the first bucket.

So take a step back, and I render just one simulation copy with the packed disks instanced to each point, and the render time of that is reasonable.

Is there a way to make the full nested setup work quickly?

Could this be because mantra doesn't do nested procedurals?