What Is Preview (and Why You Should Use It)
Subject:   Core Image
Date:   2005-08-08 14:20:28
From:   gilest
Response to: Core Image

My understanding (maybe I misunderstood??) is that Core Image is hardware dependent. The Core Image page at says: When a programmable GPU is present, Core Image utilizes the graphics card for image processing operations, freeing the CPU for other tasks.

So when iPhoto initiates one of those operations, Tiger passes it to to the GPU using Core Image, assuming the GPU meets the requirements. If not, the CPU has to do the work.