Firefox V33.0 locking up system

[Chris]

This is Firefox V33 for Ubuntu. Running on Ubuntu 14.04.1 LTS and Gnome
3.12.2. I've noticed that periodically Firefox will lockup, clock on top
task bar will quit running and I'll have to to CTRL-F1, log in and do a
sudo reboot to restart system. Thinking it may be memory I ran Memtest86
for 6hrs today with no errors noted. Could the Firefox cached web
content have anything to do with this? Last night it happened as I was
scrolling down through my Facebook feed.

Chris

-- 
Chris
KeyID 0xE372A7DA98E6705C
31.11°N 97.89°W (Elev. 1092 ft)
21:42:33 up 9:42, 1 user, load average: 0.27, 0.31, 0.28
Ubuntu 14.04.1 LTS, kernel 3.13.0-40-generic