since updating from 3.6.xx to firefox 5, 6 and now 7, firefox sometimes will freeze while loading a site and use 42-50% of cpu resource. it also sometimes doubles or trebles memory it uses at same time as freezing, and freezes for 2 or more minutes. when it comes back sometimes it will have failed to load a page and will display the url but a white screen. this can happen any site, but seems to occur more when on image sites. usually i have more than one ff window open, one of which is an iboard, and the freezing seems to occur more often when either posting, or when opening a subboard or more often a thread in tabs or new windows. problem seemed to be helped when i disabled a recently installed java plugin but didnt disappear, and it can still happen anytime with only one window/tab open. the only common thing seems to be the site is either refreshing, or loading.