Am edting DV footage and have the same problem with just one sequence. I have tested the speed to my external firewire 800 disc both ways and it looks fine in the activity monitor. I tried do set scratch disc to my internal drive and disconnected my firewire apogee soundcard but the problem is still there. If anyone have a suggestion let me know ; )
FCP 6.06
MacPro4,1
Quad-Core Intel Xeon
2.26 GHz
Memory: 8 GB