Are you running low on memory? This is has been my experience with Firefox on a laptop with 4GB. If the commit size for any of the content processes goes over

Are you running low on memory? This is has been my experience with Firefox on a laptop with 4GB. If the commit size for any of the content processes goes over 1GB, Firefox tabs stop responding. Killing the content process in task manager brings the browser back to life. Sometimes the browser slows to a crawl and CPU usage spikes (making me wonder if it's memory compression kicking in -- though I haven't verified). Other times tabs are responsive but links just make the spinner go (as if I've hit a socket limit). It's almost always fixed by killing the content processes (making sure not to kill whichever one is running addons!). I guess this is a little better than the old days when a few times a day I would just restart the whole browser.