I think that setting only relates to when Firefox restore your previous session windows and tabs, and not to tabs you open "by hand". There isn't any bult-in way to open tabs over time to reduce the strain, but that would make a good add-on. (Not sure if anyone has posted one.)

Yeah, I have Tab Mix Plus, but that doesn't seem to do it. This is one of those problems where it surprises me that nobody else has brought it up. Maybe they know about another add-on? Anybody have any suggestions?

Open bookmarks in new tab might be something to try?

Press the Alt or F10 key to bring up the tool bar. Followed by;

Windows; Tools > Options Linux; Edit > Preferences Mac; application name > Preferences

Then Tabs. Check the box next to Don't Load Tabs Until Selected.

I found a bug on file for this (request for enhancement):

• Bug #837364 – Allow the "Open in Tabs" from Bookmark menu to load tabs on demand: https://bugzilla.mozilla.org/show_bug.cgi?id=837364

It's generally not helpful to add comments to bugs (unless you can help with the code), but you can register on the Bugzilla site and "vote" for them to be fixed. See:

• Bugzilla Etiquette
• Voting

I added my vote.

Gulgs2 - I'm not sure what you mean, but I'm opening a new window, then going to a bookmark set and clicking "open all in tabs."

Gulgs2 - oh, sorry. I didn't realize you were referring to an add-on. I'll look into it.

Guigs2, that doesn't seems to work.