I had no MOS 3.0 here to test it, maybe you could give it to me 
Normally higher memory-bandwith should result in better performance.
Alas, neither do I :-( The tests were run under OSX (Leopard).
It's an interesting result, most likely due to the higher latency of DDR2 compared to DDR memory (The ~20% difference would be about right for this). Whilst DDR2 memory may be capable of four operations per memory clock, the G4 cpu isn't (in fact it doesn't use DDR at two operations per clock either).
Regardless, the lower power consumption of DDR2 should result in a greater battery life (big plus :-) ).
As with the move from SDRam to DDR on G4 systems, the rest of the system can probably benefit from using DDR2 data rates (4 ops per clock) over the system bus, although any operations via the processor FSB will be limited to using only 25% of this speed (ie single data rate).
In real-life operations DDR2 may well provide higher performance compared to DDR when f.ex DMA-ing between memory and other non-cpu peripherals, eg graphics card.
/Sorry for the extended OT :-)
