Any good tips to optimize my Powerbooks performance? Im planning on installing 1GB extra RAM but other than that are there any other simple tasks i can do to get the best out of it? I've heard defragmenting etc. is no longer neccesary on Macs as it is an in-built operation the mac performs itself 'behind the scenes'... true?

I am using Pro Tools audio editing software quite heavily at the moment and its starting to have trouble keeping up on fairly 'light' sessions, i get "Audio Processing can't keep up" sort of messages. I'd have expected more from my machine (specs below). So, any tips?

Thanks YDR

Mac Powerbook G4 (PPC) 15"
OS 10.4.9
60GB Hard Drive (with around 9GB currently free)