Hi Raft,
Sorry for confusing. It's not animation that cost performance. It's the draw calls, caused by drawing too many objects.
To reduce draw calls, we could combined the all meshes into one (thus calling only one draw call). But this way it's hard to calculate bone animation as all object mesh data is in shader.
maybe you can profile it to see what slows it down?
It doesn't slow down, to be exact. It just takes alot of computing power. I'm working on live wallpaper and computing consumption is quite critical, or else the battery will drain pretty fast.
From the previous testing in hardware skinning post, we have one object with ~1ms to animate. If 20 objects, which would take ~20ms to process. I think that 1ms is roughly spent on draw call.