Thank you for the reply. You comment:
I think you’ll probably see best results exporting a movie at Current Settings onto your external drive, then going to H.264 through Compressor. In Compressor you should exporting to a either a different external drive or your internal drive for best performance.
I am currently using my internal HDD as the scratch disk – no external drive is used anywhere in my workflow. Will using an external firewire as you suggest speed up conversion times?
Is it generally advisable to always use an external drive as the scratch disk?