Hi, I'm just about to install a new 1tb internal drive on my G5 dual 1.8 and was going to do a clean install of the OS and start copying files over. But I wondered if there is any benefit (speed, data safety) to dedicating an existing 120gb drive to system use only. Obviously performance suffers as the disk fills up, but what would be a wiser move - having all files take up half of a new 1tb drive, or dedicating an older 120gb for OS/apps use only and using the new drive for work/storage? Also, for Time Machine backups - I know the official advice is to make available double the space... but for example if I fill up say 600gb of a 1tb drive, I assume it would be fine to allocate 1.2tb of an external drive to Time Machine rather than 2tb, since some space will be unused? All advice appreciated!