I do not think there is a definite answer to that question. Both the G4 and G5 are very good at floating point computations and pretty bad at integer computations in comparison to stock x86 processors. It all depends on the software you use. Most of the "raw" benchmarks are just plain silly, what matters is real-world performance. But real-world performance depends on the OS and the Apps you use and whether thay are optimised for your platform. Apple consistently demo-ed photoshop on stage, trying to show it runs faster on a Mac thatn on a PC, however if you are not using photoshop, what do you care? If you need fast integer computation or higher FPS in a game, that comparison is not worth a penny. So, there is no consistent way to compare processors just like that across the board. Processors can be said to be efficient at a specific task, not as a whole. Then you have to take into account the other components, the FSB for instance, which is dog slow on most G4's, etc. etc.