Ah! Ah! Yes. Ok. Here’s the rather understated but incredibly-significant feature added in CS4: Pixel Bender effects.
Keven Goldsmith of Adobe explains.
Pixel Bender is Adobe’s way of packaging up (essentially) OpenGL Shader Language
The outcome will be a lot of extremely cool effects plugins. Some of these will be old effects that run much faster, meaning we can use them more freely. Some of these will new effects that would have been prohibitively slow, but are now merely non-realtime.
This is getting good.