I have built a UI where the majority of what's on screen is put there using CALayer's. The layers are fairly simple in terms of their setup; the majority have an image set as their contents and a couple have a shadow. There are also some `CALayer` derivatives such as `CATextLayer` and `CAGradientLayer`. At any one time there is about 18 layers on screen. The contents of 11 layers change frequently (*but not to represent an animation*), and the same 11 can be scrolled to the left or the right as they are embedded in a `UIScrollView`.

I have noticed that performance is a little sluggish on both my 3GS and 4 so I am looking for ways to tune what I have to hopefully improve performance somewhat.

I have set `rasterizationScale` to the appropriate scale depending on the device and have set `shouldRasterize` to `YES`.

The images are passed to the layers in the following way ...

`someLayer.contents = (id)someUIImage.CGImage`

Is there anything else I can do to improved the overall performance?