Yes, this is the major dealbreaker for me and why I can't justify using it at Uni and on the go. What's more, the heat output during certain workloads is just too much.

Chrome used to be a similar offender, except they have gotten it under control, even though it's not quite as efficient as Safari.

I also noticed the huge too. Hopefully they can do something with this soon!

Same for me with Firefox Developer Edition :(

I tried to install different versions of Firefox too. No luck so far.

I've had the same issue for years now on my non-retina MacBook Pro, two MacBook Airs and retina MacBook Pro (2017). I've tried everything, from disabling all my add-ons to reinstalling macOS.

Every time Firefox is updated I give it a try, but the issue persists, even with Firefox 57 and Firefox Nightly 58.

Me too. The battery drain and heat generation is profound with FF vs Safari.

I bet /u/good_grief can provide some debugging/logging steps for folks to look at here.

We're investigating this in bug 1404042.

Which version of macOS are you running, /u/pok3rr?

I think it generally doesn't help that firefox is getting better at doing multi-threading, it's getting a quite heavy speed up due to better utilizing available resources, which in turn can quite easily mean a bigger burden as well.

Sure ? I imagine multi-threading means that Firefox uses more CPU for a shorter time. The same calculations are done, but they don't use as much energy because they are quicker. Is that wrong ?

Yes, after this Quantum project enters the fine tuning stage, I think a natural step following that is an ”Are we environmental yet?” initiative, like the ”Are we fast yet” and ”Are we slim yet”.

This performance with perhaps some important discoveries around energy consumption to boot would really complete my picture of the next-gen Firefox.

So, I did some basic tests on my own, running Safari 11 and Nightly side by side, playing the same videos in Youtube, and then Netflix. The results are...not looking good for Firefox, TBH. I tried again to just run Firefox by itself in Safe mode, but for some reason the energy impact soared up to 200(!).

I barely can use my Mac more than 1h30m running Firefox at 50% brightness so yeah I can feel you!

Updating this: I've been using just Safari for a day or so, and my 'average' energy index is up super high (90-something!) after doing little more than showing off some photos and a bit of google maps for a presentation today. I'm starting to wonder how accurate these numbers are.

Try opening this url and see if there is a particular site causing CPU usage: about:performance

This doesn't help. Everything is just fine from that point of view.

Thank you anyway!

Hey, just wanted to let you know that this actually did help me to identify a slow tab on my setup. Thanks for alerting me to its existence!

I simply need to go to yahoo, cnn, youtube or netflix to reproduce the issue.

Firefox doing what? It obviously sits idle until you load a website in it. What sites are giving you trouble?

Static Wordpress sites, Facebook, Youtube etc. i am using uBlock Origin btw.

Yahoo, youtube, cnn, and netflix all cause significant heat and battery drain compared to using chrome or safari.

how the fuck is it possible that browsers suck that bad? it is 2017 and we have to deal with this shit. They parse some text and some photos for fucks sake! We can have smooth games in 4k and 60fps but a fucking browser displaying text is lagging. I dont even care one uses graphic card. It is unacceptable. Chrome, FF and others, all guilty of this travesty.

I don't think "parsing some text and some photos" is nearly as complex as modern webpages.

You play games in 4k@60 on your Mac? The fairy tales.

I am having the exact same issue here. I am actually watching the battery drop. Is there any fix?

No luck so far. Sorry man!

I too am having this problem. I have to use Safari on my 2016 MBP because FF even simply browsing a site like Yahoo or CNN or watching netflix or youtube becomes a massive battery drain and heats up my laptop unbelievably. Not so with Safari. This happened both with Sierra and is still happening with the latest FF version on high sierra.

Interestingly, I saw this article which confirms battery issue with FF. This is with windows but it still seems relevant. https://www.yahoo.com/news/browser-gives-best-battery-life-234505618.html

Disable smooth scrolling and see if it improves. On my (modern) machine it uses 11% instead of 4% of CPU while scrolling. Major resource hog.

Mine isn't activated so I think it's not because of it.

Anyway glad that you have fixed it!

Stating the obvious: if you have some add-ons can you try deactivating them?

I use uBlock Origin + RES only.

I tried to refresh Firefox with new profile. I even tried to run it without addons. No luck.

I hope Quantum DOM can finally make a difference here?

I've installed firefox 57 on a new macbook pro and only moved over the bookmarks, passwords and session (lots of tabs open, but most of them haven't loaded) from my old machine. Sometimes firefoxcp webcontent uses 400% cpu. Can't figure out what causes it, though. At the moment it's behaving alright.

Firefox on my MBA seems to make my temps run higher than usual and eat my battery. Any plans or a timeline for Firefox to play nicer with macOS?

I think it would be more fair to say that Chrome and specially Safari are very power optimized.

Firefox has finally improved its foundation and that gives hope that power optimizations can now be implemented.

I'm using FF 57 in macOS 10.13 and the worst thing is watching videos. Normally the battery comsuption is not that bad, but whenever I start playing a video, the CPU usage goes to near 75-100% and well, battery goes with it.

Hardware video decoding seems to be disabled for even h.264 on MacOS :-( I have checked this with the DevTools Media Panel add-on. Does anyone know how to turn it on? Thanks!

debugInfo : {

Container Type : "MediaSource"
Audio Decoder(audio/mp4a-latm) : "apple coremedia decoder"

... Video Decoder(video/avc, 256x144 @ 30.00) : "apple software VT decoder" Hardware Video Decoding : "disabled" ...

I also suffer from this issue (macOS Sierra 10.12.3). I have a slight suspicion that it has something to do with the rendering of the window chrome.

I monitored Firefox with a single tab of with about:blank in idle mode without being activated and tried to focus on the window. This put Firefox almost at the top of the CPU usage.

Wow! I tried to do the same thing before!

Hey all, as I have posted yesterday in https://www.reddit.com/r/firefox/comments/7e0r4f/battery_lasts_longer_on_rmbp_by_reducing_frame/

There is a way to improve MacBook's battery life when using Firefox in exchange of smooth rendering/animation. I am using Firefox Nightly, but it should be applicable to the most recent stable version of Firefox...?

In summary: 1. open about:config 2. set layout.frame_rate to e.g. 20

A good explanation of what layout.frame_rate does: https://www.reddit.com/r/firefox/comments/65h2k3/layoutframe_rateprecise/

Notice this last link talks of layout.frame_rate.precise being obsolete, but in one of the comments mstange explains what layout.frame_rate does.

Hope this helps. Cheers

Thank you a lot. Gotta give this a try!

Yeah Firefox is really shit on certain websites on my Macbooks. Things like linkedin, youtube, io9 etc just bring the laptop to its knees. Works fine in Linux and Windows, but this is really irritating. I still use it, but try to avoid certain sites if i can.

One of the things I've noticed is that some sites can switch on the dedicated GPU if you have one, and that can destroy your battery.

If you go to Activity Monitor > Energy, do you have "Requires High Perf GPU" as a column, and is anything in there saying Yes?

Firefox is not in the list :(

My battery life/heat generation remains terrible with FF57 and my MBP just has the Intel Iris onchip GPU.

I know that it's an old thread, but I've stumbled upon it while trying to find a solution for same problem. I have a 2017 MBP running Sierra, and right now FFDevEdtition is having Avg Energy Impact of 59.8, with the closest WebStorm with AEI of 8... This is unacceptable. I'll have to get back to Chrome until the issue is resolved.

I had 50% CPU from windowserver, then I added the title bar and the dark theme and it dropped to 20%. hope it helps

Go to customize, then check "title bar".

My Mac has been running slow over the last few days.. Shortly before that, I started trying out FireFox Quantum.

I finally had enough when the small magnetic connector that is touching the laptop got hot enough to actually burn me. I starting looking at activity monitor and promptly closed FireFox quantum for good.

https://imgur.com/yer6Vcl

I only had about 8 tabs open, one of which was pinned (google play music) and only installed a few plugins. I don't think I was doing anything significant enough to deserve to get literally burned.

Yup, I actually thought my macbook battery was getting old / broken in the last weeks (only like 4 hours instead of 10), until I realized that it only happens when Firefox is open. After few years on Chromium, I switched back to FF recently. But this ain't gonna work for me. Hoping to come back as soon as this is sorted out.

Opera with "battery saver" is pretty good as well. I wish Firefox would make something similar.

Weird. I'm running Nightly on my Macbook pro and I've got an average energy impact of 26.64, according to the energy meter.

To be honest, my energy impact in Activity Monitor is only 12... It is not trustable I think