Firefox integrates into some platforms better than others. There are some proposed changes to fix this, but they aren't quick fixes.

>Write bindings to all relevant OS composition libraries. For Windows, we already have DirectComposition bindings, and for Linux, there are already bindings to Wayland. We need bindings for macOS Core Animation (which runs in the window server on relatively recent versions of macOS) and Android SurfaceFlinger.

https://github.com/servo/webrender/issues/3115

On the Mac you can pick up performance improvements now by opting out of the OS's window scaling feature for the Firefox app.

Get info for the Firefox app in the Finder and select the option to "Open in Low Resolution".

Count me as one of the people for whom Firefox runs butter smooth on my Mac. Never slows down or gets janky.

Very strange how there is such wide discrepancies in experiences for Mac users.

If they want to gain market-share they should prioritize Macs, since most web developers these days prefer them. The more developers who use Firefox, the more it'll get tested with, the better support it'll have.

My understanding from reading the bug reports is that the general cause of macOS performance issues is understood, but to do anything about it with the current architecture would require pulling developers off WebRender development instead. Instead, work is being done to make things better there for when that's ready to ship on Mac.

Is there any way to provide incentives to devs to prioritize mac development? Like a bug bounty of sorts?

I'd happily contribute to a patreon or something if it meant increasing the chances of having a usable version of firefox on my mac at some point.

To think that Mozilla can have revenue of $500M+ per year, yet a Patreon might be needed to make their browser faster :-)

The problem in osx is not that it's slow, but the ridiculous amount of cpu (and therefore battery) it consumes.

For the people who suffer the bugs ( which seems to be a majority of users that have a retina display, and specifically those who use it set on high resolution) just opening firefox will quickly lead to the macbook's fans spinning at full throttle and battery drain. There are issues opened and development supposedly in progress, but it's been like that for months if not years. At this point I would take whatever could speed up the process...

If Firefox is chewing through all your CPU from the moment it opens you need to reset your profile.

https://support.mozilla.org/en-US/kb/profile-manager-create-...

I don't think Firefox can fix all the bugs at the same pace Chromium can.

I've uninstalled and installed Firefox several times during the years, in different machines even (MacBooks between 2013 and current models). Same feeling from most developers working at my workplace (~1000 devs in the building, not one using FF on a Mac ).

For some reason every time I talk about these bugs on the internet people treat it as a weird edge case I'm going through, but talking IRL with people about Firefox everyone seems to know how unusable it is in a Mac - not only in my circle of acquaintances.

Reinstalling Firefox on a Mac is not the same as doing a Firefox Refresh. The former only touches the executable while the latter cleans up cruft in your Firefox data (potentially lingering around from legacy extensions).

I understand that, but I assume both of those are still "shallower" ways of resetting than actually switching computers, which I've done several times (for unrelated reasons ofc) and I've seen no improvement...

Is that true outside of US?

I'm not sure. But the benefit it provides is a Linux-ish environment that you don't have to tinker with constantly to keep it running, which is a potent combination. And web devs don't care about fine-grained hardware control/compatibility.

You know, I wonder if it's GPU-bound. Macs often have weaker GPUs than Windows machines, and this could explain the inconsistent results people are mentioning in the thread.

You may be hitting this: https://bugzilla.mozilla.org/show_bug.cgi?id=1429522

Firefox does not use Core Animation, unlike Chrome and Safari, which causes an extra full-window blit on GPU in some cases. It also uses a transparent window, so macOS has to composite the content behind the window whenever Firefox draws. I have a patch in there to improve things, as well as a crate planeshift to help the situation with WebRender, but the patch causes some usability regressions so it has not landed. In the meantime you can set gfx.compositor.glcontext.opaque to true in about:config to get an opaque window at the cost of rounded window corners and vibrancy.

I highly doubt this is the case. I can't tell the difference between my gaming desktop and my laptop with integrated graphics.

From what I've seen on the chromium bug tracker, Google has been on a ~5 year crusade to improve Mac performance. Around half the issues Ive seen include something like "We don't know what Mac does here, let's ask some people at the next conference" (these were core rendering performance bugs). I totally get why Firefox can't compete with that. It's fast on the platforms that don't seem to be hell-bent on making custom rendering slow.

Ah-hah!

"What if we stopped trying to guess what layers we need? What if we removed this boundary between painting and compositing and just went back to painting every pixel on every frame?

This may sound like a ridiculous idea, but it actually has some precedent. Modern day video games repaint every pixel, and they maintain 60 frames per second more reliably than browsers do. And they do it in an unexpected way… instead of creating these invalidation rectangles and layers to minimize what they need to paint, they just repaint the whole screen.

Wouldn’t rendering a web page like that be way slower?

If we paint on the CPU, it would be. But GPUs are designed to make this work."

https://hacks.mozilla.org/2017/10/the-whole-web-at-maximum-f...

Are you being sarcastic? I can't tell.

Any modern CPU and GPU can do a lot of DMA and copying of memory in a very short amount of time, but that doesn't mean it'll be efficient wrt. power... which is what I think you were 'complaining' about?

The GPUs can do it, push 60 page updates per second, but that is very energy inefficient way to do it.

You can feel this by playing any 3D shooter on your laptop and see the battery being sucked empty.

Nope. I'm on a Mac with a powerful GPU and Firefox still sucks.

Some anecdata: I haven’t had performance issues with Firefox on Mac for a very long time. I’ve had more issues with Firefox on Windows than I have on Mac.

As for Chrome, I used to use it a lot, but the privacy concerns and controls it comes with bothered me too much to want to continue to use it on any of my systems.

Firefox containers are also essential to me while browsing the web - I don’t know if Chrome provides anything similar.