Ubuntu 18.04 hangs when using Google Chrome, Mozilla Firefox and Thunderbird [duplicate]
Solution 1:
There was a documented, since resolved GNOME problem with memory leaks in 18.04 LTS. Details on its resolution are in Bug 1763878 and 1672297. It has also been resolved in 18.10 and 19.04. 16.04 LTS uses Unity, not GNOME, and therefore does not exhibit the issue.