Over the years, Mozilla has made great inroads in taming Firefox's appetite for memory through initiatives such as MemShrink, which slashed memory utilization by as much as 50 percent. While the enablement of multi-process browsing in Firefox may negatively impact memory utilization, it may end up being a case of short term pain for long term gain while Electrolysis matures.The first stable Firefox release with multi-process capability is expected to be Firefox 46, which is slated for release on April 19, 2016.
Via: Neowin