If that were the case and it was the rendering of points, I would expect to see the same jerkiness in Processing 1.x since it would be a GPU bottleneck, but I don't. It runs perfectly fine in prior versions.
I'm not sure how much needs to go on, as it's not rendering a circle point, but a sprite tied to a vertex. I even turn off the smoothing, so its just a square sprite. I would think processing triple the vertex count, triple the color buffer (not applicable in this example I think), along with billboard rotation would cost more than adjusting the point size. At least, in my prior tests when comparing textured quads to point sprites, the sprites were way faster.
I'm not sure how much needs to go on, as it's not rendering a circle point, but a sprite tied to a vertex. I even turn off the smoothing, so its just a square sprite. I would think processing triple the vertex count, triple the color buffer (not applicable in this example I think), along with billboard rotation would cost more than adjusting the point size. At least, in my prior tests when comparing textured quads to point sprites, the sprites were way faster.