[apazzolini]

Unfortunately, looks like the CPU spikes are still a problem on OS X for me.

I check this every time a new version is released as I'd love to make the switch from Chrome, but Firefox with one blank tab and no extensions uses more CPU than Chrome with 15 actual tabs. When I actually throw activity at Firefox it hogs the CPU even more.

Here's hoping v61 addresses it.

[mccr8]

That sounds kind of like a known issue with scaled resolution on OSX. Unfortunately, it doesn't look like any progress has been made on it.

https://bugzilla.mozilla.org/show_bug.cgi?id=1404042

[cimmanom]

Aha! That detail (that it's specific to scaled resolution) explains so much!

[apazzolini]

I unfortunately notice this behavior even when my MBP (2013, Retina) is in clamshell mode hooked up to a 1440p monitor rendering at native resolution. :(

[derekdahmer]

My hackintosh with a dedicated GPU has no problem at all because it has the rendering power to handle it. But my 2014 MBP Retina with integrated graphics gets destroyed and ends up spiking the CPU as well.

[apazzolini]

I have the top of the line model from 2013 with 16GB RAM and discrete graphics (forced to always be used in energy saver prefs).

Firefox feels very fast and doesn't lag while being used, but the unnecessary CPU spikes kill my battery. We're talking about one page open at about:blank with no extensions and a completely fresh profile spiking to 20% CPU usage every 10 or so seconds.

[diggan]

I'm unsure if this is actually Firefox fault. I'm running Linux (arch and Ubuntu), Windows and macOS, and Firefox is only slow on macOS, while my macOS machine is the second most powerful machine I have. Running Firefox in a Ubuntu VM on macOS is faster than running it natively on macOS.

[Paul-ish]

Regardless who is technically at fault, the Firefox team is best placed to resolve the issue.

It kind of surprises me that this is an issue at all. I was under the impression a large number of FF devs use Macbooks.

[spiderfarmer]

Yeah, well they know what the problem is but it fails to get a high enough priority to get solved: https://bugzilla.mozilla.org/show_bug.cgi?id=1407536

[pcwalton]

It is highly unlikely that this single issue is responsible for everything reported in this thread.

[vanderZwan]

I find this confusing: there is tons of discussion in the thread, and yet:

> UNCONFIRMED

> Votes: 0 votes

[spiderfarmer]

Yeah plus I find it strange that their telemetry isn’t picking this up.

[jamienicol]

Hi, I'm one of the commenters on that bug.

The discussion is all specific to that page. The biggest issue is that the animations are being driven from Javascript instead of CSS, so there's little we can do to optimize it.

The rest of the discussion is possible heuristics we can implement to optimize how we layerize the page. It would potentially help on this page, but might make things slower elsewhere.

[spiderfarmer]

The problem is not with that page. A simple CSS animation without JS triggers the same issues.

[jamienicol]

Sorry I don't check hackernews for replies frequently.

That bug refers to high cpu load on that page. On that page it is due to the animation being driven from javascript.

If a simple CSS animation causes high cpu usage please file a separate bug with an attached test case.

[Paul-ish]

If it is a JS vs CSS issue, why does it only slow things down on macOS?

[jamienicol]

The site in question on that bug is CPU heavy on all platforms

[BuckRogers]

They do use a lot of Macbooks but Windows users get priority care since they're the meat of their market.

[ComputerGuru]

So you’re proposing this is a macOS gremlin that appears only with Firefox?

Don’t you think it’s more likely there is a bug in macOS-specific Firefox code?

[Avshalom]

Well the thing is it seems to only affect every other mac user even with otherwise identical hardware and os version.

If I had to guess I would chalk it up to a qc issue on some Apple specific chipset that just doesn't get hit by the other browsers code paths and just doesn't get noticed in other less used, less intensive apps.

How to diagnose it or work around it is beyond me.

[diggan]

Well, all cross-platform browsers run slower on macOS than other OSes, at least in my limited testing.

[vondur]

I agree. Firefox seems to run really well on Linux, but seems to just feel slow on MacOS.

[lwansbrough]

Of course it's Firefox's fault. Chrome works fine.

[CyberDildonics]

If other web browsers don't do it, how is it not firefox's fault?

[grumblestumble]

Chiming in here. I would absolutely love to switch to Firefox for a host of reasons, ranging from "I don't want to use Google products" to "I love the tabs". Unfortunately, it's completely unusable for my workflow on a 2015 Macbook Pro with 16G RAM. I keep a variety of tabs pinned (JIRA, Zeplin, Gitlab, Jenkins, Invision, etc) and it seems as if they continue to hog a disproportionate amount of resources even when in the background, which is not an issue on Chrome.

[AsyncAwait]

> Unfortunately, it's completely unusable for my workflow on a 2015 Macbook Pro with 16G RAM

I run Arch Linux on this exact hardware and Firefox runs amazingly well there. It only runs like crap under macOS, which makes me think there's something with macOS specifically that's going on there.

[mercer]

I really want to switch to Firefox, so every once in a while I force myself to use it 'properly' for a week or two at least.

Such a two week period has just ended, and while FF does feel snappier than before, I'm running into exactly the issues you describe. When using Firefox, my four-year old MacBook Air pretty regularly slows down to the point where my music starts stuttering and even force-closing FF takes a while. I've had bluetooth devices disconnect too.

Now if it was just that, I could perhaps accept that maybe my laptop just can't handle my browsing behavior anymore. Unfortunately the same thing happens on my 16GB RAM Mac Mini. Not as often, but still.

I don't have these problems with Chrome, even when I clearly have too many tabs open for my memory to handle. Occasionally my music will stutter when I open multiple gmail tabs in Safari (I use Safari for stuff like email and banking), but it's rare, and nothing like what happens with Firefox.

[xenophonf]

I wonder what's causing that on your computer, because I'm running Firefox on a late-2011 MacBook Pro without any issues, and that's with a ton of tabs opened (including a bunch of pinned tabs running multiple instances of Office 365 in separate containers, Slack, and so forth) and the usual crowd of extensions (UBO et al). It's bouncing between 0 and 5% CPU utilization.

[mercer]

I've tried figuring it out, but haven't been able to pin it down. Is it even possible to check tab resource usage the way I can in Chrome? If not, that's another reason I'd probably keep coming back to the latter.

Thing is, it's not even that I have so many tabs open. It's always been fewer than Chrome, and with fewer active extensions to boot. Furthermore, it also happens on my other computer. The other one has 16 Gb of RAM, so it can handle quite a bit more, but the problem happens often enough that I also switched back to Chrome there.

[hedning]

There's about:performance but it's not as full featured as chrome's resource usage view unfortunately.

[sgc]

I had to stop using FF on windows when it tanked because I disabled hardware acceleration (to force google maps to stuff their stupid 3d satellite images in the can). Look at the your rendering settings would be my random guess.

[staktrace]

You can get more detailed memory usage information by going to about:memory

[kleiba]

I experience regular "gray outs" on Ubuntu with FF hogging so many resources that eventually the only thing that works is killing it. This happens to me both on a 5 year old desktop as well as on old Lenovo Thinkpad (X2002s). However, I believe flashplayer to be the culprit as I often have quite a few youtube tabs open -- obviously never more than one playing though.

[StudentStuff]

Why are you using Flash Player for Youtube? I've gone nearly 4 years since installing Flash on any machine, its pretty well unnecessary today. If you want to reduce performance though, using Flash is one way of going about it.

[Narishma]

Depends on your hardware and drivers. On a couple of my older machines the Flash plugin is the only way I can get hardware accelerated video decoding.

[zaphirplane]

It’s usually the profile (some tweet years ago, some bad setting ) would be great if Mozilla had some solution for this other than zap your profile. Alternatively it’s an addon they have.

[psteinweber]

I'm in the exact same boat. Trying since a year to switch (back) to FF, but my testing period always end in frustration. Chrome is much more "snappy" in all regards.

[unethical_ban]

I just don't understand this. Furthermore, I don't know if I've ever seen a "scientific" test of FF vs. Chrome using real world apps.

At work, I have several GUIs in browsers that I access through Chrome, and they cause instant 3+ GB of usage. I can't test FF due to group policy, but anyway, Chrome can be a hog, too.

Are you saying that those same half dozen apps, when pinned in Chrome, do not cause any RAM issues for you?

[acranox]

Reading so many comments like this confuse me. I run an older mac, and I find firefox very stable. It's with chrome that I have all the problems you're describing. Every time I'm forced to use Chrome, I'm reminded how unusable it is. But I'm in the minority it seems.

[Kpourdeilami]

It is borderline unusable on the most recent Macbook Pro and most recent version of OS X. Weird that it only seems to affect some people

[stouset]

Strangely, none of my coworkers seem to have problems. But every release seems to get worse; first it was terrible performance, then fonts in pages and the UI became blurry. This happens even on newly-installed MBPs, so it’s doesn’t seem like it could be related to anything I’ve done. And yet… coworkers don’t have problems.

[spiderfarmer]

A profile refresh is useless in this case.

[dralley]

Try a profile refresh

[stouset]

Tried. No success. I've also fully-uninstalled it with CleanMyMac, also to no success.

[zaphirplane]

Why do you think a piece of software running on your laptop would behave differently from millions running on the same hardware. Profile, addon, custom install location, weird env variables

[jhatax]

have you changed the resolution of your display to be "scaled" in system preferences? does setting it to "default for display" make FF usable again?

[stouset]

I keep it at scaled to max resolution, but I reverted to default and it made no difference.

[greglindahl]

If it affected everyone all of the time, it would have been fixed.

[cat199]

sierra (not high sierra) and latest 15/4c MBP.

Has been working just fine here for 7-9mo since I got it (not on the latest latest, but this sounds like an ongoing issue)

Agree it's weird.

[azinman2]

I’m on a 5k iMac with zero problems on latest OS X.

[buu700]

Yep, regardless of whose "fault" it is — and I totally buy that it's macOS's fault, considering how much effort my startup Cyph has to spend on working around Safari/iOS bugs — at the end of the day Firefox is unusable for me if my battery won't last for any reasonable amount of time and I have to deal with a kernel panic every other day.

Really hoping this gets sorted out soon, because on most other counts I prefer the current Firefox to Chrome. (The other thing keeping me on Chrome is pinch-to-zoom support.)

[thiagocmoraes]

I really want Firefox to succeed, but I got this behavior since Quantum was launched. I'm still hopeful to see it solved.

[Blindedwino]

Same issue here with v60. I really, really want to move away from Chrome but I just can't, it's unusable on my MBP.

[lwansbrough]

I was gonna submit a performance profile as a bug report, but the https://perf-html.io profiler doesn't work in FF60

[dblohm7]

Umm, it should be working. Can you provide more details, please?

[bradknowles]

It worked fine for me, just a few seconds ago.

What specific problems are you seeing?

[Rotdhizon]

Maybe related: Does anyone have the issue of a few number of FF tabs showing up as several in task manager? Say I have 2 or 3 tabs open, it'll show something like 7-10 in task manager. And yes, they are hogging a ton of RAM, upwards of half of a 16GB setup

[adpirz]

At least good to hear I'm not the only one. I want to like it for all of its speed and sleekness, but it regularly runs hot and gets the fans going full blast. Odd that it's still an issue.

[mosselman]

I have the same issue on my MBP Late 2013, but on my MBP 2017 everything works smooth. Not as smooth as chrome, but nothing really noticeable. I always have 40+ tabs open.

[butz]

Have you reported this bug? It's all fine on the old OS X Mavericks.

[spiderfarmer]

I reported it and they know what the problem is but it got marked as no-priority. Everytime there’s a new release I check if it’s solved and move back to Safari. Every release there are people complaining about it. I know I have been for 2 years now, but it falls on deaf ears.

[sayhello]

Might be hardware related. Did you provide your HW profile in the bug report?

[spiderfarmer]

Yes, twice.

[cat199]

issue ref?

[spiderfarmer]

See above.

[k_bx]

Also, opening Facebook is like a step-by-step strategy.

[h1d]

What is the reason that you want to switch?

[leandot]

Same here, still not usable on my mac

[jklinger410]

It feels like they just traded RAM usage for CPU usage.

[NVRM]

The exact opposite from gnu