Heard of Electrolysis Project (for short called as ‘e10s’)? Which Mozilla has been working on since a long time to run web content in a separate process from Firefox, till now you can enable e10s in Nightly by setting values of browser.tabs.remote and browser.tabs.remote.autostart preferences to true. FYI, you can open a ‘New e10s Window’ from the menu without touching the preferences in about:config.

The tabs that are opened in a separate process have their title underlined. To the latest, Mozilla is now prompting Nightly users to test this feature, and a new option, ‘Enable E10s’ has been added to (in-content) Preferences and available to enable or disable under ‘Startup‘ in ‘General’.

Nightly shows notification to test  e10s

Advantages with the Multiprocess Firefox model

"The two major advantages of this model are security and performance. Security would improve because the content processes could be sandboxed (although sandboxing the content processes is a separate project from Electrolysis)." Electrolysis Wiki page says.

" Performance would improve because the browser UI would not be affected by poor performance of content code (be it layout or JavaScript). Also, content processes could be isolated from each other, which would have similar security and performance benefits. "

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