Firefox 4.0 RAM usage soars over time in Mac OSX 10.6.7 and is never freed
Firefox 4.0 RAM usage typically averages between 400-750MB for light usage (1-2 windows, 1-3 tabs each). Memory usage skyrockets over time, and/or if I open more tabs or windows where I've seen it consume well over 1 GB of RAM of my total 4 GB. Firefox 4.0 never seems to free much of this RAM relative to what it's consuming either.
The only plugins enabled are QuickTime, Flash and Java (and disabling any of these to use Firefox efficiently should not be required).
The worst I've ever seen was it using 1.27 GB of RAM when all I had open was Facebook (1 window, 0 tabs). Something is not right with this browser...Shouldn't it free what it isn't using?