I'm curious about what scratch disk some of you use? Do any of you use just your internal drive as a scratch disk or do you use a portable external? I'm Thinking about getting a hitachi 7k320 and replacing my current 160GB 5400 rpm drive. then i could put the spare 160GB in a firewire enclosure but I'm wondering what would yield better performance Either: 1. run the scratch disk on the new hitachi drive OR 2. run the scratch disk off of the portable firewire drive The internal drive is faster but also has to handle OS work as well but the external drive is only a 5400 rpm drive. What do some of you guys/gals use?