I have looked around quite a bit, and haven’t found clear requirements for CUDA on the Mac, apart maybe for supported graphics cards.
CUDA 2.2 requires MacOS 10.5.4. Fine, my machine runs 10.5.7. I have a Quadro FX 4500… well, not really listed. But, hang on, nVidia does not seem to mention anywhere that Intel processors are a requirement. The nVidia installers did let me install everything.
Of course, after reboot, the kext will not load on my Quad G5. Of course, compiling the SDK will not work as soon as it tries to use Intel binaries. But… this was’t mentionned.