Here is a useful post from Ashley:
[quote:trgxjjy6]Layers have virtually no performance impact unless you:
1) add a shader effect
2) change the opacity from 100%
3) change the blend mode to something other than "normal"
4) enable "force own texture"
All of the above will force the layer to render to an intermediate texture, which has a memory and GPU fillrate overhead. Note parallax has no effect, it does not cause this.
We would probably need to see your .capx to see what is really going on.
can i pm you (and send you the capx)
thanks