thegman: Comparisons with other operating systems are not always appropriate. Other operating systems have a tendency to get slower with every iteration. (It's one of these sad facts, even despite developer efforts to avoid it). But most RISC OS developments, including RISC OS 5, tend to make things faster with new releases, not slower.
Long may that continue.
If the G5 ran at twice the clock speed of the G4, with the cache, disk access and so forth to back it up, and similar features, then I doubt anyone would be using a G4 Mac even if they *were* the only ones to have Mac OS X 10.3 or whatever. (Does this comparison look silly now? It's your comparison).