Firefox 64-bit is now available to download

Victek said:

I believe the move to 64 bit Windows was driven mainly by the desire to install/utilize more than four gigs of ram.

Kernel Patch Protection aka PatchGuard, is a feature of 64 bit versions of Windows and was first introduced with XP x64. Whether it's good or bad is hotly debated and needs a separate thread :)

Note that if you use a 32 bit operating system you will only be able to run 32 bit software.

I haven't studied the WoW64 vulnerability article yet. For the moment it makes sense to use 64 bit apps that are internet facing when possible.

Actual on 32 bit windows 10, 8.1 or 7 you can actually use some 16 bit software using NTVDM.

BunnyJ said:

Given that the vast majority of processors are 64bit it would only make sense to use a 64bit OS with it.

WoW64, Windows subsystem that allows 32-bit software to run on 64-bit Windows machines. A sizeable sample of Duo customers shows some disturbing numbers in terms of vulnerable users. For example, 80 percent of browsers in the researchers’ sample size were 32-bit processes executing on a 64-bit host running WOW64, putting them all at risk. EMET remains a viable protection for Windows users, one that Microsoft has marketed many times as a temporary stopgap between the disclosure of a zero-day vulnerability and the availability of a patch. But in the WoW64 example, EMET can be completely bypassed

The soft spot, the researchers said, is the WoW64, Windows subsystem that allows 32-bit software to run on 64-bit Windows machines. A sizeable sample of Duo customers shows some disturbing numbers in terms of vulnerable users. For example, 80 percent of browsers in the researchers’ sample size were 32-bit processes executing on a 64-bit host running WOW64, putting them all at risk.

If EMET can be bypassed, wouldn't be safer to use windows 32 bit operating even on 64 bit machine especially if your machine only has 4 gb of ram and you don't plan to upgrade the memory?

tried firefox 64bit since 42 release day

few things worth to mention for people considering moving to 64bit version over 32bit:
1. you can install both on your system and using same profile, BUT you cant run both at same time
so if u run 64bit, then u need to close it before run 32bit

mozilla dev. also didnt split installation shortcut, so like in start menu, it will only showing the lastest installed firefox
ex. if u install 64bit then 32bit... the only listed shortcut in startmenu is 32bit

2. basically firefox 64bit remove most of plugins (java.silverlight)... this what make people feel more snappier i guess
less plugin to load = more resources
32bit remain same (included plugins) but seems mozilla decide to remove it by end of year
NPAPI Plugins in Firefox | Future Releases

as i am using massive tabs (1000+)
i didnt really see big different in memory usage nor performance increase

Great,i was waiting so longfor this release!

For me the 64bit version is way faster then 32. I say this because I am used to read a news page everyday:
Le Figaro - Actualités

Just try to load this page and see for yourself the difference! For me the page loads instantaneously and
I can scroll down right after I open the page with 64bit FF. But with the 32bit it is much slower and scrolling
make it hang for few secs.

BunnyJ said:

It would seem to me that if such a issue existed it would leave just about every computer that uses a 64bit OS vulnerability. And I for one find it hard to believe that MS would let such an issue get out in the wild. Also, I would like to see more than one source to verify those claims.

Just my 2c on this subject.

Just for info, you can click on the links, you can find a 19 page study pdf file on how they did it. I read it. Some didn't really make any sense.

What I got form the report, which is just my opinion. That windows 7 64 bit isn't as vulnerable as the windows 8.x & 10 64 bit system. It has some doing do with how the ntdll.dll writes to memory. The issue comes when ntdll.dll writes above 4gb but for some reason it seems to write better on windows 7 64 bit.

For me, I don't think I would be effected by it either way. My machine only has 4 gb of memory, which would force the ntdll.dll to write below 4 gb. They recommend using 64 bit software that will be accessing the internet instead of 32 bit software.

Does edge run in 64 bit mode or 32 bit mode?

Tried it. Does not work sometimes in certain financial institutions when adding data.
For once Edge did something this release of FF could not do.
Shipinomore