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Comment by f311a | Hacker News Reader

I've switched to Firefox on most of my devices.

And there is only one thing which I don't like — high CPU usage compared to chrome. It makes my old MacBook air very noisy because of the fan spinning. When I use chrome it's completely silent.

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Interestingly, for me Chrome is the browser that causes my machine to sound like a helicopter on take off (though maybe my usage is atypical). Safari still has the best power efficiency on the macOS, but between Firefox and Chrome anecdotally it seems like a toss up.

Would be curious to see some actual benchmarks comparing the latest browsers, does anyone do those on a regular basis? A quick google search didn't turn up anything more recent than last december: http://themainframe.ca/comparing-firefox-chrome-and-safari-b...

Same experience here on a MBP. Tried to switch a couple months ago and the fans run in overdrive.

It’s a known issue that pops up in every FF thread. But it’s hopeless. Everytime it pops up some people subscribe to the issue and thats it.

https://bugzilla.mozilla.org/show_bug.cgi?id=1407536

Honestly, I’ve given up on Firefox.

Especially on YouTube where I believe there’s an issue with Firefox not using the most efficient encoding on the videos.

Do you have details? I noticed that Youtube on Firefox makes the fan spin up on my 2013 rMBP a lot. I currently use Firefox but as a heavy Youtube watcher this is a pretty big negative.

Same here. I have been a longtime Firefox user and don't recall having performance issues with YouTube on macbook before Quantum. But now if I'm watching anything more than a short clip on YouTube, the MBP's fans start to annoy me and it feels like it is going to burn a hole in my lap. YouTube in Chrome is totally fine. YouTube on Firefox on my Windows Intel NUC desktop is also totally fine. It seems to be a mac only Firefox issue. Would really love a solution!

Firefox uses H.264 for YouTube on macOS, so it can use the system's H.264 hardware decoder, which should be faster and use less power than a software decoder. Chrome uses a VP9 software decoder on YouTube. You can try VP9 in Firefox by setting the about:config pref "media.mediasource.webm.enabled" = true, but it is disabled by default for good reasons. :)

This YouTube page will show which codecs are currently enabled in your browser: https://www.youtube.com/html5

This is because Youtube pushes VP8/VP9-encoded video by default to save on bandwidth. Unfortunately, absence of a hardware decoder consumes a ton of battery. Both Firefox and Chrome receive VP9 encoded video.

Safari doesn't understand VP9. So Youtube pushes H.264 video which can be hardware accelerated.

To force youtube to send H264 in firefox/chrome you need something like https://addons.mozilla.org/en-US/firefox/addon/h264ify/

Firefox uses H.264 for YouTube on macOS, so it can use the system's H.264 hardware decoder.

This YouTube page will show which codecs are currently enabled in your browser: https://www.youtube.com/html5

Same here, if I'm watching YouTube on my 2015 rMBP I have to use Safari rather than Firefox if I don't want the fans to spin up.

Yeah I’ll dig up he bugzilla link and add to this comment.

Off chance, do you use html5 video?

I do. For me, it looks like Firefox is struggling with rendering when it comes to any kind of animation/effects, e.g videos, images, as well as js powered animations using SVG/canvas. Even simple things make my laptop boil.

Maybe I'm wrong about CPU and it's all about integrated Intel GPU.

Do you have a blacklisted GPU driver? https://wiki.mozilla.org/Blocklisting/Blocked_Graphics_Drive...

You can check in about:support whether it is disabled. There's a section at the bottom of the article about how to force-enable various features if you want to see how glitchy it really is on your machine.

I'm having similar issues on a fairly modern laptop with i7-7700hq and GTX1050. After a few minutes of watching YouTube, it gets all jerky and not smooth. I'm guessing something is throttling, though video playback isn't taking a high percentage of either the CPU or the GPU. I tried forcing the builtin Intel GPU on firefox.exe, that didn't change anything.

See if the video codec is shown in "Stats for Nerds". Perhaps hardware decoding for either webm or h264 isn't enabled.

YouTube prefers VP9, when available. You can try disabling VP9 in Firefox by setting the about:config pref "media.mediasource.webm.enabled" = false. Depending on your GPU, Firefox may be able to decode H.264 using a hardware decoder.

This YouTube page will show which codecs are currently enabled in your browser: https://www.youtube.com/html5

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