Geekpatrol has some benchmarking results comparing an Intel-based Apple MacBook Pro and a recent G4-based PowerBook.

The MacBook Pro outperformed the PowerBook G4 in almost every benchmark (especially the multi-threaded benchmarks). Since all of the MacBook Pro’s baseline scores are over 100, it even outperformed our baseline system, a Power Mac G5 1.6GHz!
Check out the piece.