Pretty much becomes unusable

If the video is encoded using a codec your hardware doesn't handle, it would be left up to the CPU to decode. Av1 can slow everything down to a crawl over CPU. You'd think the browser would be smart about the stream selection though.

Youtube has been turning on AV1 for 1080p content for me. My phone is the only device with an AV1 hardware decoder. The impact on battery life and CPU usage has been extreme.

You can tell Youtube to prefer AV1 only for low-quality videos (https://www.youtube.com/account_playback) or you can install an extension that will force h264 playback where supported.

Other playback features such as ambient mode and volume equalisation can also impact performance, though that kind of depends on how fast your web browser is at executing Javascript, and to a much smaller extent.

The substantial bandwidth savings are here to stay, though, so in time I think Youtube will move to AV1 more often.

I have noticed Google sites showing what looks like some form of memory leak. Typically it's only Microsoft websites doing this.

Tangially related; imgur uses (and used) 100% CPU for me; I was never quite sure how or why.

The reason I bring it up is because I tried to actually profile it a handful of times, but my C++/Rust/Python knowledge was completely useless in the face of a browser development toolchain.

Did I miss something, or is it not possible to easily see what functions take the meat of javascript execution time?

(it feels really absurd if it's not easy, given that people can essentially serve whatever arbitrary script they want and my computer pretty much has to deal with it if I want to use whatever site)

Disabling “Ambient Mode” in the settings helps cpu usage a lot on my intel MBA.

If you have an adblocker it might be intentional.

Worth checking the browser console. If you use a content blocker (e.g. uBlock Origin) it may block things the site really, really "wants". It then goes into an extreme busy loop and throws exceptions to the console like a berserker on a nightly rampage.

Once you carefully whitelist the resource it wants the CPU usage goes down again. At least that fixed it for me (I was mistakenly checking various codec related settings in Firefox first too to find a solution.)

A great (free and O.S.) Android client with ad blocker is

https://github.com/polymorphicshade/Tubular

it also integrates SponsorBlock!

Thought it was just me! This started happening just today.

YouTube is pretty shocking in Firefox, even worse with an ad blocker.

Somewhat relevant: can somebody share good mpv defaults (or some other interesting technique) for playing YT videos? I have managed to get it to work, but it still pauses a lot for bufferring. I wonder if there's maybe some yt-dlp, ffmpeg, etc. trick to pre-cache some segments or something like that. The reason to play it in mpv is not to avoid commercials (I have a paid account), but because I can then play it from my editor while fully controlling the playback - it works great for watching lectures and taking notes.

Tried [Invidious](https://github.com/iv-org/invidious)? It's really lightweight. I host my own instance: https://iv.duti.dev and it works wonders (Librewolf with strictest fingerprint resist)

Sorry to hijack, but...

I have weird issues with YouTube on my home PC. If I have a Chrome window with a YouTube video running to the side of my monitor, it always inevitably ends up freezing up the whole display. Ctrl+Alt+Delete and cancelling back in makes it go away briefly, however sometimes it can just keep freezing the monitor up constantly.

The weird thing is, the PC (running Windows 11) has a powerful graphics card which can handle AAA games (as of earlier this year at least), graphics drivers are all up to date, and YouTube works fine in fullscreen across the whole ultra-wide monitor.

I just can't work out what's causing it. It makes running YouTube side-by-side with other programs a real pain in the ass. It's been like this for months now. Checked browser HWA settings, and they're all as they should be.

As others have noted, if you don't have hardware decoding for the codec being used, it will suck up a huge amount of cpu. Last year I got a new Macbook Pro with M3 Pro cpu, and it's amazing how little cpu it uses for video playback. After watching an hour of Youtube, the battery is down only about 5 or 10%.

Livechats are particularly bad.

For desktop, the extension HyperChat was made to address whatever programming is leading the livechat system to blowing up your CPU.

https://livetl.app/hyperchat

Have only noticed this on my Windows machine, not any of my Macs. The windows machine has enough horsepower to use most of it's 2000w power supply, so I don't think it's a hardware issue. Using firefox engine & an adblocker fwiw.

When I open the "My Videos" tab, then I get this problem, otherwise it works.

Also: Recently my videos "goes full black" for few milliseconds (not matter which way to see them, but yt is where I noted it more). I'm on M3, and can't pin point a reason.

Edge has been freezing on me for months with over 100% CPU usage. I finally figured out it was a youtube downloader extension. I disabled it and the problem went away.

On the few occasions I visit I noticed excessive CPU usage with their crappy "ambient" mode.

I have not and don’t run an adblocker fwiw.

Also happens with Github and anything that uses ads lately. A 2 core PC dies while trying to render those pages.

I've had something similar happen starting maybe a year ago, and varying in intensity from "no problem" up to "pegged CPU in the youtube tab and UI actions can lag up to several seconds". It doesn't affect video playback though.

This behavior comes and goes over time, for example it's been fine for several weeks in a row now. I assume it's punishment for running an ad-blocker.

If you have an adblocker and it happens at the start of a video then this is intentional

I have like 4 simple tabs and my Chrome is hogging 1.8GBs of RAM.

No other context, huh? Not even browser and OS? If youtube itself was stuttering, 100M daily users would flip out. So narrow it down. For example if you add the word Edge to your search you might find settings like Video SuperResolution that can tax your CPU https://www.reddit.com/r/LinusTechTips/comments/1bcmmdo/micr...

I pretty much only watch YouTube via the app on my phone, rarely in a browser. I also pay for Premium. Have not noticed any recent/new issues.

Disable ambient mode.

It can use a ridiculous amount of CPU.

It seems hardware accelerated only on windows chrome.

This started happening on one of my older computers recently and I had to actually disable hardware acceleration to get the audio to stop being out of sync. The tradeoff for that has been noticeable frame dropping. I even added an extension to force h264 but there's no difference.

It can play video no problem on other sites or in VLC. It's just YouTube and just on that PC...That PC can run Doom Eternal. Video content shouldn't be a problem.

Yes, happens to me in the last few days.

I thought it was Firefox going bananas after some update, but I’m glad to find out it’s just another user hostile ploy from the owning class

It's probably the special Google hardware obsoleting sauce called AV1. Without hardware acceleration your computer will struggle to decode their videos.

I keep getting the video restarting after a few seconds randomly, very annoying even more so when it's the ad that restarts from the beginning, which almost seems intentional. Like a bug that nobody is in a hurry to fix.