Part of CachyOS Wiki Notes. From the official CachyOS wiki (last updated 2026-06-14).

Optimized Repositories and x86-64 Levels

CachyOS recompiles Arch packages for x86-64-v3, x86-64-v4, and Zen4+.

• x86-64-v3: 5–20% performance uplift over baseline x86-64.

• x86-64-v4: substantial gains via AVX512, workload-dependent.

• Zen 4/5: v4 plus extra instructions:

  abm, adx, aes, avx512bf16, avx512bitalg, avx512ifma, avx512vbmi, avx512vbmi2, avx512vnni,avx512vpopctndq, clflushopt, clwb, clzero, fsgsbase, gfni, mwaitx, pclmul, pku, prfchw,rpdid, rdrnd, rdseed, sha, sse4a, vaes, vockmulqdq, wbnoinvd, savec, xsaveopt, xsaves
  

Customized packages

The CachyOS-PKGBUILDs repo carries packages with ongoing updates, patches and backported fixes. Selective PGO, LTO and BOLT optimizations; some -git packages are maintained (e.g. mesa-git). Search at https://packages.cachyos.org/ (shows compilation architecture, last update date, etc.).

Migrating x86-64-v3 → x86-64-v4 or znver4

Trap: Intel 12th gen (Alder Lake) and newer may report x86-64-v4 but cannot run AVX-512 — P-cores support it, E-cores do not, which causes instability. Intel disabled it via microcode/BIOS updates (early chips; re-enable only by avoiding/rolling back microcode) and by hardware fusing (2022+ chips, permanent). Treat these CPUs as x86-64-v3 only.

Verify v4 support:

/lib/ld-linux-x86-64.so.2 --help | grep supported

A x86-64-v4 (supported, searched) line means supported; no v4 line means unsupported. Example:

$ /lib/ld-linux-x86-64.so.2 --help | grep supported
  x86-64-v2 (supported, searched)
  x86-64-v3 (supported, searched)
  x86-64-v4 (supported, searched)

For AMD Zen 4/5, check the reported arch:

gcc -march=native -Q --help=target 2>&1 | grep -Po "^\s+-march=\s+\K(\w+)$"

Output znver4 or znver5 means you can migrate. Both x86-64-v4 and znver4 use the same mirrorlist: /etc/pacman.d/cachyos-v4-mirrorlist.

Migration steps:

1. Edit /etc/pacman.conf, replacing the x86-64-v3 repos. Keep [cachyos], [core], [extra], [multilib] unchanged:

   [cachyos-v4]
   Include = /etc/pacman.d/cachyos-v4-mirrorlist
    
   [cachyos-core-v4]
   Include = /etc/pacman.d/cachyos-v4-mirrorlist
    
   [cachyos-extra-v4]
   Include = /etc/pacman.d/cachyos-v4-mirrorlist

2. Clear cache and sync DBs:

   sudo pacman -Scc   # Confirm with 'y' twice
   sudo pacman -Sy

3. Reinstall everything to switch architecture:

   pacman -Qqn | sudo pacman -S -

4. Reboot.

Adding these repos to an existing Arch install

Check the CPU compatibility list in Preparing a CachyOS USB Installer first. Then the automated script (detects CPU instruction sets, installs the most optimized repos, backs up the old pacman.conf):

curl https://mirror.cachyos.org/cachyos-repo.tar.xz -o cachyos-repo.tar.xz
tar xvf cachyos-repo.tar.xz && cd cachyos-repo
sudo ./cachyos-repo.sh

Uninstalling the repos

curl https://mirror.cachyos.org/cachyos-repo.tar.xz -o cachyos-repo.tar.xz
tar xvf cachyos-repo.tar.xz
cd cachyos-repo
sudo ./cachyos-repo.sh --remove

Benchmarks

Phoronix (Michael Larabel) has benchmarked CachyOS repeatedly since 2022 — including an Arch x86_64-v2 RFC (2021), “The Performance Of Arch Linux Powered CachyOS” (2022-09-12), “Arch Linux CachyOS Benchmarks Of x86-64-v3 & x86-64-v4 Repositories” (2024-02-29), and a Ryzen 9 9950X OS comparison (2024-08-20). Caveat noted on the page: Liquid-DSP and RocksDB were compiled by the Phoronix suite ignoring /etc/makepkg.conf flags, giving unexpected CachyOS results.