🦆 ducksteps
A custom Windows build of Firefox ESR, compiled from source with Zen 5 or AVX2 CPU tuning, full LTO, and tuned PGO enabled.
🤔 Why ducksteps exists
Google killing Manifest V2 support, combined with OAuth2 breakage in Chromium, forced me off my previous browser (Chromium_Clang). Firefox had the best extension compatibility, but the official Windows build leaves a lot of CPU performance on the table. So I built my own. ducksteps is compiled with:
🎯 -march=znver5 -mtune=znver5 — Zen 5 instruction set and tuning, not a generic x86-64 baseline
OR
-march=x86-64-v3 -mtune=generic — AVX2 instruction set and tuning, (also) not a generic x86-64 baseline
🔗 Full LTO — link-time optimization across the entire binary
🧠 PGO — profile-guided optimization trained on 80+ real browsing workloads
🦾 clang-cl / lld-link — LLVM toolchain throughout, no MSVC codegen
The result is a browser that benchmarks noticeably higher than the official release on the same hardware.
📋 Requirements
OS: Windows 11 (64-bit) CPU: AMD Zen 5 architecture:
✅ Ryzen 9000 series (9600X, 9700X, 9900X, 9950X, 9950X3D, etc.)
✅ Ryzen AI 300 series
✅ Threadripper PRO 9000 series
✅ EPYC 9005 series
🖳 AVX2 Legacy Version now available for most CPUs made around 2013-15 or later.
GPU: Any — tested on RTX 4080 Super
If you're running a Ryzen 9000 series, Ryzen AI 300 series, Threadripper PRO 9000 series, or EPYC 9005 series — this build is compiled specifically for your silicon. Zen 5 only; no Intel equivalent exists.
If your CPU has AVX2, BMI1, BMI2, FMA, LZCNT, MOVBE, and POPCNT — download the Legacy version. In practice: most Intel chips from Haswell (2013) onward and most AMD chips from Excavator (2015) onward qualify. If you're unsure, check your CPU specs against that feature list before downloading.
📥 Download
Grab the correct installer or standalone ZIP from the Releases page.
ducksteps.X.X.X.Setup.exe —ZEN5 Installer — installs like a normal app
ducksteps.X.X.X.Standalone.7z — ZEN5 Portable — extract and run, no installation
ducksteps.X.X.X.Legacy.Setup.exe — Installer for older PCs — installs like a normal app
ducksteps.X.X.X.Legacy.Standalone.7z — Portable for older PCs — extract and run, no installation
SHA256 hashes and VirusTotal results are included with every release.
⚖️ Legal
ducksteps is an unofficial build. "Firefox" and the Firefox logo are trademarks of Mozilla. ducksteps is not affiliated with or endorsed by Mozilla.
Source: mozilla-firefox/firefox. Licensed under MPL 2.0.
🤷 Honest notes
This is the first thing I've ever compiled into something I could share, and I am extremely inexperienced. Starting with a web browser was probably not the smartest "Hello World" project, but I wanted a browser that fully utilized my 9950X3D and this is what I ended up with. I hope you enjoy it!
I relied heavily on ChatGPT and Claude to get across both the start and finish lines. Human feedback is always welcome — open an issue or hit the Discussions tab.