> Mac OS X 10.4: Uses the LLVM JIT for optimizing many parts of the OpenGL pipeline, including emulating vertex/pixel shaders when hardware support is missing, performing texture format conversion before uploading to the GPU, efficiently packing GPU buffers for vertex submission, and many others.
> Mac OS X 10.6: The OpenCL GPGPU implementation is built on Clang and LLVM compiler technology. This requires parsing an extended dialect of C at runtime and JIT compiling it to run on the CPU, GPU, or both at the same time.