For opening that many tabs at once, your computer should flog you for being a sadist !
Oh no, that would only be if i choose to open all my bookmarks at once!
But upon launching Firefox, and choosing the session (yes, there are many) from Session Manager, then they are ready for access quite quickly, and open in about 2 secs upon clicking on them the first time. I choose "Don't load tabs until selected" (Firefox Options>>General) and am not even using hardware acceleration (Firefox Options>Advanced>General). Yet an SSD would make it even faster. Thank God for options.