Using Ubuntu 16.04 64-bit, Firefox 49.
Firefox is slow to restart when many tabs are open, although most of them are not loaded by default (only one tab is loaded in each window when restarting Firefox).
Firefox responds very slowly when many tabs are open (however not loaded), when I try for example to change tabs, load a new tab, etc.
All the above are much faster when only a few tabs are open or even loaded in Firefox.
As Firefox RAM goes beyond 5GB, it gets very slow to respond. However there is still a lot of free RAM on my system. So what's the point in getting more RAM?
It looks like a fundamentally bad implementation:
Unloaded tabs should not slow down the application.
Even loaded tabs should not slow down the application when there is plenty of free RAM.
New window should not have to load all the add-ons (it looks like that's what it does which takes a long time).
Are there ways to correct this situation?