merged the threads - if you fear a post gets out of sight please bump it up rather than opening a new thread ...
a few ideas: your disk for sample data is set to *not journaled*, yes?
are there any other firewire devices attached - the bus might become buisy unecpectedly then.
any background tasks running on the macbook gathering CPU from time to time?
basically i would think it runs better on the intel than on the PPC ....
christian
and remember: only a CRAY can run an endless loop in just three seconds.