Mozilla has already said they will never implement 3 because it's pointless. Separate processes per tab make the browser slower, not faster. Crash resilience is

Mozilla has already said they will never implement 3 because it's pointless. Separate processes per tab make the browser slower, not faster. Crash resilience is obtained through sandboxing the plugins that were crashing in the first place (hi Flash!), instead of entire browser instances. It's one of the reasons Firefox uses less memory than Chrome.