Oh, that's why that kept happening on my Macbook pro? I thought I was loading a broken site or had too many tabs open like I always do.

For me adding "Auto Tab Disard" [1] (a Firefox equivalent of The Great Suspender for Chrome) has reduced my FF memory/CPU footprint by 10x. It defaults to 10 minutes which is usually long enough where you've mostly forgotten about the tab, then it will refresh when you focus on it. A feature fortunately becoming native to FF. I don't seem to have the previous performance issues anymore but I'll be looking for it now.

[1] https://addons.mozilla.org/en-CA/firefox/addon/auto-tab-disc...

> Oh, that's why that kept happening on my Macbook pro? I thought I was loading a broken site or had too many tabs open like I always do.

That's what I thought as well, but apparently it's something to do with the compositor and FF redrawing the whole window instead of just relevant pixels or areas - which provokes a lot of unneeded calculations -something specially damaging for users that have scaling set to more space (effectively a higher resolution).

That was my understanding at least, when I first learned about the bug many months ago. I followed the development for a while with no (public) improvements and now I just wait for news about the issue or something, but all FF related news so far have been about new features or products.

I really hate to be a “works on my machine” kind of person, but I’ve been running FF Nightly for personal stuff and FF Developer Edition for work on a variety of Macs for at least three years now and have literally never had any problem.

I am not trying to cast doubt on your experience, but I just wanted to point out that it isn’t universal!

It's really weird, because some people I talk to has never noticed a problem, yet I've been able to reproduce it (unwillingly) every time I've tried to install firefox on any macbook - different machines, different OS version, clean installs, you name it. It's just a matter of installing FF and using it lightly for some minutes (different websites too, or just showing the start page in the background) and the fans are already at full speed.

It makes me really confused because my current understanding on the bug doesn't seem to be compatible with the idea of only affecting some users - and to be clear I'm not casting doubt on your experience either, it's just hard to imagine how a performance issue regarding the compositor and screen redrawing could be affecting users differently.

Make a repro checklist and file a bug, if it's so easy to reproduce for you! Write down what you do, as you do it, and maybe devs could then repro it too!

Yeah, it's a shame that Firefox is unusable on Macbooks.

Subconsciously I started using Chrome on my Desktop more regularly too, since the abhorrent state of Firefox on Macbooks trained me into using Chrome instead.

The Firefox developers don't seem to care about the state of Firefox, on macOS, to be honest.

For example - This is a bug report I made 7 months ago of an issue that would be quick to implement, yet make a noticeable difference in UI on macOS (move the Share menu to the File menu). Nobody has bothered to respond. https://bugzilla.mozilla.org/show_bug.cgi?id=1512851

I'm with you on this, Firefox for osx is in very bad shape, i can only use it on my strong imac. Chrome had to stay on macbook :(

Also, touchpad zoom on mbp is still not a thing in ff.

I run mostly with my laptop closed and two external monitors and the only time FF makes the fans run is one particular site (dailykos.com) which seems to make the CPU go nuts.

Otherwise, I've always been on FF from the Netscape days. I use Chrome when I have to (noticably Hangouts for a while), but otherwise stayed with FF without a problem.

That's odd. I'm on a 2015 MBP with Mojave, and I recently switched from Chrome to Firefox because Chrome started causing intermitted freezes (even the mouse pointer wouldn't move). I've been on Firefox (and Safari) for over a week now. No issues.

Do you have your MBP screen's resolution set to "more space" on system preferences -> displays? Are you using an external monitor for FF?

(Just curious about how your setup differs from mine)

Sounds weird to me too. I've been using FF as my main driver on mac, high sierra then Mojave and I never had this problem. If anything it's google chrome helper that often becomes crazy eating my CPU cycles for just 4 tabs.