There used to be a memory fix for older versions of Firefox 2 but when 3 came around the folks at Mozilla felt confident it’d be better at memory management. They were wrong. It did stuttering wonders to iTunes because Firefox and iTunes are the two biggest memory users.
Well, now there’s Memory Fox. It’s reduced my Firefox memory usage from over 200MB down to 100MB. It just flushes the memory on a constant basis that way the turds that Firefox leaves don’t accumulate and cause your system to do stuttering wonders.