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If you want to reduce memory usage—especially during long livestream sessions—consider using "YouTube Boost Chat"

🧠 YouTube Super Fast Chat

🚀 Ultimate Performance Boost for YouTube Live Chats

📌 What Does This Userscript Do?

YouTube Super Fast Chat drastically improves the performance and responsiveness of YouTube's live chat interface (including live chat replay). By re-engineering how chat messages are processed, rendered, and displayed, it provides a much smoother experience, especially during high-volume streams or VOD replays.

✨ Highlights

• Zero-lag chat rendering even during fast-paced streams.
• Enhanced timestamp accuracy for live chat replays.
• Correct message & ticker ordering based strictly on message timestamps.
• Memory leak prevention for long sessions.
• Font pre-rendering to eliminate "pop-in" text.
• Visual stability fixes for tooltips, author chips, and menus.

🧰 Key Features

• 🧩 Advanced Chat Message Stamping – Significantly improves how quickly messages appear.
• ⏱️ Accurate Replay Timing – Fixes replay chat timestamp desync issues.
• 🔁 Timestamp-Sorted Rendering – Ensures chat messages and ticker items are displayed in proper chronological order.
• 🧼 Memory Leak Patches – Resolves known memory leaks in YouTube’s own ticker and timer handlers.
• 💬 Reduced Message Limit – Caps max rendered messages (default 90) for better performance.
• 🖼️ Optimized Thumbnails – Smaller author/emoji images to lower memory and CPU usage.
• 🧠 Smart Prefetching – DNS and resource preloading for smoother emoji/images loading.
• 🛑 Fixes Chat UI Glitches – Includes layout fixes, border bugs, tooltip overflows, and misaligned buttons.
• 🧱 Disables Inefficient Transforms – Removes YouTube’s unnecessary animations and will-change properties.
• 📜 Refined Scroll Behavior – Ensures stable scrolling, proper anchor behavior, and fixes anchor jumping bugs.
• 🎯 Ticker Animation Engine – Custom-built CSS and JS for ticker (Super Chat/Membership) rendering and progress bars.

❌ What It Doesn’t Do

• 🚫 It does not alter chat moderation, censorship, or content.
• 🚫 It does not inject ads or track your browsing.
• 🚫 It does not bypass YouTube’s core limitations (e.g., hidden messages).
• 🚫 It does not add new features like filters, popouts, or user tagging.

🌐 Where It Runs

• https://www.youtube.com/live_chat*
• https://www.youtube.com/live_chat_replay*

Works on both live stream chat and chat replay pages.

🧪 Browser Compatibility

⚠️ Not compatible with Waterfox Classic or outdated browsers that lack modern CSS/JS APIs (IntersectionObserver, CSS.supports, WebAssembly, etc.)

🔒 Security & Privacy

• 🛡️ No external tracking.
• 🔍 No analytics, data logging, or user fingerprinting.
• 📁 Uses only public APIs and resources.
• ✅ All injected logic stays within YouTube’s chat iframe scope.
• 🔐 Safe and open-source under MIT license.

❤️ Tip

If you use BetterStreamChat or other enhancements, this script should remain compatible as long as those do not override the same rendering functions. For best results, run this as the first userscript (@run-at document-start) in the list.

Sample Link (Pressure Test) https://www.youtube.com/watch?v=CQaUs-vNgXo

Sample Link (Few Comment Reply) https://www.youtube.com/watch?v=GxNlHOX4nXI

Sample Link (No Chat Message) https://www.youtube.com/watch?v=V8yKR1nI3L8