Yes, Firefox is pretty much unbeatable in performance per tab. I just installed the tab counter addon and it reports that I currently have >1500 tabs open in Firefox. I know from experience that if I run just a tenth of that in Chromium the whole system will basically lock up. And as pretty much every other more conventional browser is based on Chromium nowadays there's no alternative really unless I get a RAM upgrade.

You can see the tab count without an addon. It's not pretty, but you can do it.

Go to: about:telemetry#scalars-tab

Then look at: browser.engagement.max_concurrent_tab_count

Ah, but if you use https://addons.mozilla.org/en-US/firefox/addon/tab-stats/ then you can not only get the count, but also be able to mass-close large numbers of tabs (eg specific duplicate URLs, or everything for specific domains). A tab hoarder's best friend.

(Pretty clever to use telemetry for this, though.)

I use Firefox out of principle and because of Sidebery, but WOW, Chromium is faster by a lot from my experience. That is fresh Chromium vs. configured and used Firefox, though.

thanks for getting Sidebery on my radar! I tried treestyletabs and unfortunately it felt somewhat disappointing given how much people seem to like it.

At a first try Sidebery looks and feels more modern/slick! Might be what I was looking for!

Firefox recently rolled out an update that broke up the big GC passes into small GC passes. That contributed to a huge improvement in responsiveness.

That sounds great. But as someone who works on the Firefox GC team, I gotta say: what?

Or more specifically, I'm wondering what change you could be referring to. We've had incremental GC for many years now, which does exactly what you describe. It's true that we keep splitting up more of the uninterruptible pieces into smaller chunks, but I don't recall any major change there recently. (I'm not very good at marketing, am I?)

And according to telemetry, the incremental slices have been working quite well for most people, at least within the last dozen releases or so. We have a budget, and it's rare that we go over it. Not that I fully trust telemetry; if you have counterexamples please file a bug. (I'd love to have a nice set of scenarios that are problematic for the GC. Our telemetry errs strongly on the side of privacy, as it should, so I can't get URLs automatically.)

May I ask you about the “big picture” of how Firefox’s GC work? How does it compare to something like OpenJDK’s ZGC?

It might not have been that recent. Incremental GC was not new in the patch, what changed was the tuning. It happened some time in the last six months and was a huge improvement for the use case of realtime rendering. At the time I was comparing performance between release and nightly, and it was night and day.

That might have been related to what I was reading, it looked impressive anyway, I did mean to go check out FF then, I guess now is the time !

True but I've gone back to version 68 on Android. Latest versions don't work with s load of extensions I use. Old Reddit being one of them. And I don't care about cookies