Ok, comparing a G4 with a third party CPU-upgrade of 1,8GHz with any G4 might be not really fair

But anyway, wouldn't it be more fitting, regarding the ressources that both have, to just change the whole arround? I mean let the more Powerful MacBook do all these Tasks and use the G4 for lets say surfing on the internet (or whatever you meant with "screaming away"? (I am asking because I do not know and am just guessing, given the geekbench numbers. I know benchmarks do not say much about most reallife scenarios and I am not a benchmark ho...
I guess if someone used a G4 with 500MHz for video converting, he would see the beachball for days. My 1,33GHz G4 ibook still needs half a day to convert 1 hour of DV footage with h.264.