Windows XP Professional with Service Pack 2 - Internet Archive
Integrated drivers that allow XP to install on modern SATA/SSD drives without requiring a floppy disk for "F6" drivers during setup. Automatic Low Fragmentation Heap (LFH):
Since Windows XP Service Pack 2 (SP2) is now a legacy operating system used primarily for nostalgia, retro gaming, or specialized software, an "interesting feature" should focus on bridging the gap between its classic feel and the modern web.
You can swap parts without the OS "locking" itself.