🌿 Web CPU Tamer
Reduce your browser’s CPU usage and energy consumption by adding subtle, smart delays to JavaScript scheduling — frame-aligned, silent, and effective.
📌 What does this userscript do?
Web CPU Tamer is a lightweight performance and energy optimization script. It works by inserting tiny, precisely-timed async delays before JavaScript tasks run — giving your browser room to render, cool down, and breathe.
Websites often queue up lots of timers and animation loops that compete with rendering, input, and other system tasks. This script gently slows down how frequently those scripts run, improving overall efficiency — without breaking website functionality.
🚀 Highlights
🧠 Frame-aligned scheduling delays
The script enhances:
setTimeoutsetIntervalrequestAnimationFrame
Each scheduled task is wrapped with two async deferrals, using:
queueMicrotask — to yield within the JS task queueMutationObserver — to wait until the next browser rendering cycle
This creates a render-aware delay, ensuring the browser gets time to layout, paint, or cool the CPU before heavy scripts resume.
🤫 Stealth-compatible timing
The script adds a tiny offset to timeout delays to evade detection or interference by:
- Brave Browser (privacy patches)
- uBlock Origin (stealth scripts)
- Chrome’s heuristic throttling
This ensures the delays remain effective and invisible.
🛡️ Safe error handling
All async task wrappers isolate exceptions and safely re-throw them in the next microtask. This avoids silent failures and maintains helpful stack traces for debugging.
🧱 Clean modular design
Shared async logic is extracted into reusable helpers. Cancellation tracking is handled cleanly with Sets for setTimeout, setInterval, and requestAnimationFrame.
✅ Key Features
- ⚡ Reduces CPU wakeups and JS over-scheduling
- 🔋 Helps extend battery life on laptops and mobile
- 💻 Improves responsiveness under load
- 🤫 Bypasses Brave/uBlock/heuristic interference
- 📦 Uses only native APIs (no timers, no blocking)
- 🛑 Respects cancellation of scheduled tasks
- 🧩 Does NOT modify webpage content or logic
- 🔐 Safe, clean, and dependency-free
❌ What it doesn’t do
- ❌ It doesn’t block ads or trackers
- ❌ It doesn’t alter visuals, DOM, or network requests
- ❌ It doesn’t interfere with page layout, styles, or scripts
- ✅ It simply adjusts when tasks run — not how
🌐 Where it runs
The script runs automatically on all standard webpages:
http://*/*
https://*/*
It is excluded from direct links to:
.txt, .png, .jpg, .jpeg, .gif, .xml, .svg, .manifest, .log, .ini
So image viewers, text files, and static file URLs are unaffected.
🧪 Browser Compatibility
| Browser |
Status |
| Chrome / Chromium |
✅ Fully supported |
| Firefox |
✅ Fully supported |
| Brave |
✅ Works reliably (YouTube-safe too) |
| Edge |
✅ Fully supported |
| Safari |
⚠️ Works, but mutation timing may vary slightly |
Also works with:
- ✅ Tampermonkey
- ✅ Violentmonkey
- ✅ Greasemonkey (v4+)
🔐 Security & Privacy
- 🧠 No trackers, telemetry, or fingerprinting
- 🔒 No remote requests or hidden analytics
- 💡 Uses only local, inspectable logic
- 📜 Open source under the MIT License
🧙 Author
CY Fung
🔗 GitHub Support Page
🧾 License
MIT License
Use, modify, or redistribute freely.
