CIImage or UIImage?

[Arfaiten]

I don't know if this is the right newsgroup for this question... but is more
attinent that i found.
In a simple game that I'm writen for iPhone I use many CGAffine trasform for
reducing and rotating some UIImges. On simulator the game run without
problem, but when I try it on real device (an iPhone 2G) it run very slowly.
I read on its Class Reference that CIImage class optimize operations on
images.
Is useful for me convert all the project from using UIImage to CIImage?

Thanks,
Roberto