I am on Firefox 17.? and get frequent beta updates automatically sent for me to install.

It's going like lightning.

As I said previously, I am running Firefox 17.3 and have four windows and 45 tabs up at the moment and they all run at high speed. I think I shall bookmark them all and start again, but some I am using continuously like Radio 4 and 4Xtra so they are giving me the radio whilst I am doing something else like e-mailing or buying from Amazon.!!

I didn't say I was having any problems at all, quite the reverse, I simply pointed out that the rest of the contributors were way behind on updates, I am on 17.3 for sure, through Firefox, you may need to sign up with Mozilla to get the latest, I don't remember how I did it but it works at high speed and with lots of windows and tabs open, far better than I.E. which I keep in reserve.

Muergo is I believe using and updating from the Beta Channel not the Release Channel. http://www.mozilla.org/en-US/firefox/beta/

I don't use Beta anything, they can be buggy. After all that's why they release them so when you complain you're having problems they can fix them before the alpha release. That's not to say that the alpha release isnt full of bugs, just fewer. If you're not, consider yourself lucky.