CPU cache is not necessarily faster with a PowerMac G4 compared to Pegasos II G4. It depends on the specific PowerMac G4 model and upgrade status. I guess that non-upgraded Quicksilver and older have a slower CPU cache than Pegasos II G4. Similar regarding memory throughput (which is probably not that dependent on upgrade status): PowerMacs G4 older than Quicksilver have lower memory throughput than Pegasos II G4 I'd guess.
> is dual cpu supported??
Ruud already gave the answer in this very thread: MorphOS is going to support dual CPU configurations but utilizing only one CPU.