Ask HN: Does anyone else notice YouTube causing 100% CPU usage and stattering?

Hacker News Discussion ↗

YouTube playback is causing severe CPU spikes, stuttering, and even system freezes for many users, especially on older or less power-efficient hardware. Commenters point to several likely causes: AV1 video streams without hardware decoding, browser or GPU driver quirks, heavy UI features like “ambient mode,” and poorly implemented ad blockers or extensions, while some suspect deliberate friction for users blocking ads. Suggested mitigations include forcing H.264 instead of AV1, disabling ambient and similar effects, tweaking browser codec settings, or using alternative frontends and desktop players like Invidious or mpv.

Reported Symptoms & Context

  • Multiple users see high CPU usage, stuttering, desynchronised audio, or frozen UIs specifically on YouTube, often on otherwise capable hardware (can game or play local video fine).
  • Problems vary by platform: some see issues on Windows but not macOS, or only in Firefox-based browsers, or only after YouTube has been open for many hours.
  • Some see freezes only when YouTube is in a side window / multi‑monitor, or only in certain views (e.g., “My Videos”, live chat).

Codecs, Hardware Acceleration & Power Use

  • A major theme is AV1 vs H.264 / VP9:
    • If the browser/device lacks hardware decoding for AV1, CPU decoding can peg cores and drain battery.
    • YouTube tends to prefer bandwidth‑efficient codecs (AV1, VP9) even when that shifts power/CPU cost to clients.
  • Users report big gains by:
    • Forcing H.264 (e.g., h264ify / enhanced‑h264ify, or disabling AV1 in browser settings).
    • Checking that AV1/VP9 hardware decode is actually enabled in about:support or browser configuration.

Adblockers & “Intentional” Degradation Debate

  • Some believe slowdowns and interruptions are deliberate punishment for adblock users, citing:
    • The “Experiencing interruptions?” popup wired directly to an ad‑blocker help article.
    • Prior experiments like 5‑second delays, 3‑video limits, and frequent breakage of third‑party clients.
  • Others argue high CPU from adblockers often comes from their own heavy techniques (playlist hammering, proxying, segment removal) and/or that silent CPU spikes are a poor strategy to change user behaviour.
  • There’s broader distrust of “big tech”, countered by appeals to Hanlon’s Razor (incompetence over malice).

YouTube Features & Browser/Driver Issues

  • “Ambient mode” and “stable volume” are repeatedly cited as big CPU hogs; disabling them helps on some devices.
  • Some suspect browser ↔ GPU driver quirks, multi‑GPU setups, or browser‑specific polyfills/user‑agent paths affecting performance.

Workarounds & Alternatives

  • Suggested mitigations: disable ambient mode, tweak AV1 settings in YouTube account, block AV1 in browser, or force H.264 via extensions.
  • Alternatives include playing via mpv/yt‑dlp, Invidious instances, or third‑party mobile clients with integrated ad‑blocking.

Debugging & Profiling

  • For memory/CPU leaks: use Firefox/Chrome devtools (performance and memory snapshots, flame graphs) to identify problematic scripts, though minification/obfuscation makes deeper analysis hard.