Windows — 8.1 Lite Archive.org

: Lightweight builds can take up as little as 2GB of disk space, compared to the 16GB–20GB required by standard installations.

Install as usual. During setup, when asked for a key, use a generic Windows 8.1 Pro key (available on Microsoft docs) or skip. Note: Most Lite builds are pre-activated via KMS emulation. Windows 8.1 Lite Archive.org

Windows 8.1 has consistently been praised for its fast boot times, even on mechanical hard drives. In a benchmark comparison of six Windows versions running on identical hardware, Windows 8.1 booted the fastest—quicker than Windows 7, Windows 10, and Windows 11. A Lite version, with even fewer services loading at startup, should boot even faster. : Lightweight builds can take up as little