I think Firefox needs another MemShrink initiative. After Electrolysis / e10 - at least in my experience - the browser uses more memory over time than Chrome.
And the "Fission" project (i.e. running each browsing origin in its own process) won't help in that regard.
To be fair, they are working intensively on reducing the overhead of having loads of separate content processes, but the target goal I have heard about is still "only" < 10 MB overhead per content process, which still translates into 1 GB (!) of additional RAM usage for the benchmark browsing session with 100 separate origins (which is perhaps slightly more than the average user uses, but for power users it might not be that unlikely to hit - and it's not just tabs that need to be counted, but every iframe that loads some third-party content and therefore needs to run in a separate process, too).
I tolerate (apparently) a 6G memory leak with 50+ tabs and Tree Style Tabs. It was much faster when Mozilla accidentally remotely disabled extensions for a weekend.
