My 1Ghz G4 iMac with 768mb seems to be getting sluggish. Safari is always giving me beachballs when switching from one tab to the next. eBay is terribly slow in Safari and often it doesn't want to search. I'm also seeing slow downs in iMovie and iDVD. I don't have hard stats--it just seems slower and that I'm getting more beachballs. I'm going to run some of the cleanup utilities (MacJanitor or something) but I'm also thinking about replacing my 512mb SODIMM with a 1GB module. I am a typical iLife user. I use iMovie to create 10-30 minute movies, iDVD, in iPhoto I now have 4,000 pics. The 1gb module is $230. I should be able to sell my 512mb for around $80 so that would be a $150 upgrade to double my current RAM. You all think it is worth it? Can anyone recommend a good utility to run to cleanup/optimize my iMac? Thanks.