Mozilla plans to increase the number of content processes of Firefox’s multi-process architecture to four (from one) with the release of Firefox 54.
Some Firefox installations are still not eligible for Firefox’s multi-process architecture. This includes systems with accessibility tools or settings enabled. Multiple processes won’t be enabled for users with extensions either, regardless of whether those are legacy add-ons, or WebExtensions.
Mozilla ran its memory test again to determine the right number of content processes. An increase in the number of content processes for the browser always goes along with an increase in memory usage.
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