I'm trying the 64 bit Portable Nightly from here:
http://www.mozilla64...efox-64-bit-portableSo far so good. But it only shows "nightly.exe" in Task Manager. I have 10 tabs open. You would think that would be enough to trigger multi-whatever?

Edit: Logging into Sync worked with most things. FEBE doesn't seem to like it though. Any extensions Sync missed I just did Open File to the FEBE folder to install, such as Download Manager.
So far the best impression is that Outlook reacts almost normally even though I'm loading 10 tabs(unchecked the wait until selected to load tab option.)
Edit2: This is the PortableApps version. If anyone is unfamiliar with it, I recommend that you do not try to update the browser. It never works. It's better just to download the newer zip and unzip on top of the folder.
Edit3: Just for grins I installed the latest 64 bit nightly, 37.0a10 from
http://www.mozilla64bit.com/ It picked up settings from the portable. It seems a bit snappier. It still only shows one entry in Task Manager. But memory used is about 350 MB as opposed to 440 MB or so in Portable doing about the same stuff. I assume with that much memory it must be running lots of threads or something. It feels responsive. I don't notice anything weird yet.

Edit4: Seems stable enough I set it as default browser. I haven't watched any videos yet. But normal browsing seems fine.