The browser is now split into as many as four processes to help run content across tabs, which should result in better performance and lower memory usage.
Four content processes is the "just-right" number for Firefox because it's enough memory to ensure a fast and stable browser, but doesn't hog available memory shared by other desktop apps, according to Mozilla.
Mozilla's tests found that Windows Chrome used 1.77 times the memory of the Firefox 64-bit edition, and more than twice the memory of Firefox 32-bit. Chrome also used 1.36 times the memory of 64-bit Firefox on macOS and 1.42 times more memory than 64-bit Firefox on Ubuntu.
According to the Firefox maker, the results are due to the "liberal" way Chrome uses memory for new tabs compared with Firefox, which creates new processes for up to four tabs, while additional tabs are handled in "threads" within each process that shares the same browser engine.
Chrome by comparison will create 10 processes for 10 tabs with different sites in them, each with its own memory and own instance of Chrome's Blink engine.
It has gradually been dialing up its exposure to users, but while Mozilla hoped to have this feature rolled out by the first half of 2017, multi-process Firefox has only been enabled for about half of all users, a spokesperson toldVentureBeat.
For those with E10S Firefox, it should help lower memory computers handle busy pages such as Facebook's newsfeed more smoothly.
Mozilla also says it is on track to introduce new browser engine optimizations from its Quantum project by the end of 2017. Quantum will allow the browser engine to make better use of multi-core CPUs and GPUs to improve its performance within content processes.