High CPU issues on Firefox
From what I saw, it seems that if the preference file gets a bit excessive in size for a pref entry, Firefox starts manifesting the high thread CPU problem.
NoScript seems to be the culprit. Specifically the user_pref("capability.policy.maonoscript.sites", ...) line in the preference which gets excessively large as you use NoScript.
For the time being, I just periodically trim the list to contain only the ones I regularly visit. However, a better fix would have to be done by either the NoScript developer or Firefox.
For the NoScript dev, I think the list of sites should be moved out of the preference file and kept on its own database. Either a plain text file which generates a BDB file for memory efficiency (the BDB file contains the same data as the text file, but it is stored in a structure that can be searched very quickly, but the data does not remain in memory).
