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64 Bit (x64): Planned? Are there advantages?

Posted: Fri Apr 21, 2017 4:02 am
by MHX
I noticed that Mozilla offers 64 Bit Firefox and that there are plans that during an auto-update a 32 Bit version will be replaced on x64 systems with 64 Bit version.

I still use x86 version on Windows 10 x64. Does somebody here have experience with Firefox 64 Bit?
Is it planned for FirefoxCE to offer two versions (x86 and x64)?

Re: 64 Bit (x64): Planned? Are there advantages?

Posted: Tue Sep 19, 2017 12:54 pm
by MonkeyBoy
Basically the biggest advantage (that I'm aware of) to x64 is the ability to access more than 2GB of RAM per firefox.exe process. 32-bit Windows applications are limited to 2GB because the other 2GB is used by Windows for hardware and similar functions.

In the legacy versions of Firefox every tab runs in the same firefox.exe process, which with memory leaks in plugins, addons, and Firefox itself could end up bumping up against this 2GB limit. In the newer versions of Firefox each tab runs a separate firefox.exe process, so each tab is less likely to bump up against the 2GB limit.

The legacy limitation of x64 was that very few NPAPI plugins (like Flash, Java, Acrobat, etc.) were x64 compatible, so you lost most of your NPAPI plugins. However the newer versions of Firefox have basically removed NPAPI support for everything except Flash, so the plugins whether x86 or x64 aren't working.

With multiprocess Firefox (electrolysis or e10s) the need for x64 has really dwindled, since each tab is unlikely to exceed 2GB. Obviously if you're on a system that executes 64-bit tasks much faster than 32-bit tasks then there would be efficiencies there.