upgrade to El Capitan

Does your Mac meet the system specs...

OS X El Capitan - Technical Specifications

It sounds like you are too light on RAM for 10.11

Why not use Safari? The browser that comes with you Mac & operating system.

Look at SeaMonkey.

http://www.seamonkey-project.org/

If you do not need the built-in mail client, you can set-up SeaMonkey with just the web browser, alone.

SeaMonkey is based on the same open sourced underpinnings as Mozilla FireFox and still uses user installed add-ons and is still being fully developed and supported for older OS X versions.

BTW,

Firefox updates will still be coming for OS X10.6-10.8 until late June, possiblly, early July, so theorecally, you could stay using that last version of Firefox, at least, until the end of the year, if you prefer.

Unless there is some major security issue that affects Mac OS X Snow Leopard through the older FF web browser or a Firefox security breach, then I may stick with the final version of Firefox for awhile to see how "things" pan out.

Good Luck!

Safari on !0.6 Snow Leopard has not had ANY type of updates for a very long time and has been a security risk for a very long time.

If any one is still running OS X 10.6-10.8, forget using Safari.

There will be no more app OR security updates for Safari under these older versions of OS X.

Both Google Chrome and Mozilla Firefox are following suit by ending support for these web browsers under the same older OS X versions, too!

Of course ! Staying with current security measures is the underlying concept behind this whole thread. Thank you for pointing that out.

You're very welcome!

🙂