just installed version 7450 on ibook g4 1.33,1.5g ram,tiger
-still some minor lag at times on some 360p tubes but better then ff,camino,safari
will use as default browser...as has sidebar and is nice and fast.
couple tweaks:
i find if you like using bookmarks sidebar a great extension is "autoclose bookmarks and history" closes folders when moving on to next one...
http://www.sephiroth-j.de/1/mozilla/
to stop animation of tabs when opening "about:config" animate/browser tabs ...off