For many years Firefox was my browser of choice. I liked the constant stream of innovations and appreciated the ethos and privacy promises of Mozilla, underpinned by the fact that the code has always been open source. However, I don't believe in browser monogamy and if something better comes along I will use it, often stringing three or four browsers along at once.
For a couple of years Firefox has been absent from my favourites list. I have been lured away by the charms of Opera and Chrome and latterly Brave with barely a backward glance to my old pal. The reason for this is that on my aging company-issue Windows laptop the fox ran like a dog. An old dog. With gout. Even on my more powerful home PC it was significantly outperformed by the snappier Chromium-based browsers. Laggy and ponderous, its performance would get worse the longer it was left open, eventually using so much RAM that it would take everything else down with it. Chrome is often accused of being a memory hog, but in my experience Firefox was worse.
Now, I'm happy to say, Firefox is back. I've been using Firefox 54 and the beta Firefox 55 for a week on my work machine, and while I don't have any benchmarks to bring to bear, I can say it is a huge and very obvious improvement, with all the pauses and sticky scrolling behaviour banished. While it still seems to use more RAM than Chrome, with both browsers open at the same time Firefox seems the faster and smoother of the two.
Mozilla says that each tab now has its own process, but that it limits the number of threads to four. This means that a heavy web page in one tab won't slow down less complex ones in other tabs. The firm clains claims it uses "significantly less RAM" across all operating systems compared to other browsers such as Chrome, which allow an infinite number of threads, particularly if a large number of tabs is open.
Whatever they've done, it seems to be working.
There have been other changes too, including in the way the browser can be configured and personalised. An innovation in the beta version I find particularly useful, being as promiscuous with search as I am with browsers, is a dropdown with the logos of installed search engines that appears automatically when you type something into the main location bar. It's fast and intuitive.
On the downside, not all plugins and extensions are compatible with the new version, so some will need to be removed or replaced.